Merge pull request #9 from eugenp/master

update with origin

.gitignore

@@ -0,0 +1,85 @@
+*/bin/*
+bin/
+
+*.class
+
+# Package Files #
+*.war
+*.ear
+
+
+# Eclipse
+.settings/
+*.project
+*.classpath
+.prefs
+*.prefs
+.metadata/
+
+# Intellij
+.idea/
+*.iml
+*.iws
+out/
+
+# VSCode
+.vscode/
+
+# Mac
+.DS_Store
+
+# Maven
+log/
+target/
+
+# Gradle
+.gradle/
+
+spring-openid/src/main/resources/application.properties
+.recommenders/
+/spring-hibernate4/nbproject/
+spring-security-openid/src/main/resources/application.properties
+
+spring-all/*.log
+
+SpringDataInjectionDemo/.mvn/wrapper/maven-wrapper.properties
+
+spring-call-getters-using-reflection/.mvn/wrapper/maven-wrapper.properties
+
+spring-check-if-a-property-is-null/.mvn/wrapper/maven-wrapper.properties
+*.springBeans
+
+20171220-JMeter.csv
+
+.factorypath
+dependency-reduced-pom.xml
+*.so
+*.dylib
+*.dll
+
+xml/src/test/resources/example_dom4j_new.xml
+xml/src/test/resources/example_dom4j_updated.xml
+xml/src/test/resources/example_jaxb_new.xml
+core-java-io/hard_link.txt
+core-java-io/target_link.txt
+core-java/src/main/java/com/baeldung/manifest/MANIFEST.MF
+ethereum/logs/
+jmeter/src/main/resources/*-JMeter.csv
+
+**/node_modules/
+**/dist
+**/tmp
+**/out-tsc
+**/nbproject/
+**/nb-configuration.xml
+core-scala/.cache-main
+core-scala/.cache-tests
+
+
+persistence-modules/hibernate5/transaction.log
+apache-avro/src/main/java/com/baeldung/avro/model/
+jta/transaction-logs/
+software-security/sql-injection-samples/derby.log
+spring-soap/src/main/java/com/baeldung/springsoap/gen/
+/report-*.json
+transaction.log

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2017 Eugen Paraschiv
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -0,0 +1,54 @@
+
+The Courses
+==============================
+
+
+Here's the new "Learn Spring" course: <br/>
+**[>> LEARN SPRING - THE MASTER CLASS](https://www.baeldung.com/learn-spring-course?utm_source=github&utm_medium=social&utm_content=tutorials&utm_campaign=ls#master-class)**
+
+Here's the Master Class of "REST With Spring" (along with the new announced Boot 2 material): <br/>
+**[>> THE REST WITH SPRING - MASTER CLASS](https://www.baeldung.com/rest-with-spring-course?utm_source=github&utm_medium=social&utm_content=tutorials&utm_campaign=rws#master-class)**
+
+And here's the Master Class of "Learn Spring Security": <br/>
+**[>> LEARN SPRING SECURITY - MASTER CLASS](https://www.baeldung.com/learn-spring-security-course?utm_source=github&utm_medium=social&utm_content=tutorials&utm_campaign=lss#master-class)**
+
+
+
+Java and Spring Tutorials
+================
+
+This project is **a collection of small and focused tutorials** - each covering a single and well defined area of development in the Java ecosystem. 
+A strong focus of these is, of course, the Spring Framework - Spring, Spring Boot and Spring Security. 
+In additional to Spring, the modules here are covering a number of aspects in Java. 
+
+
+Building the project
+====================
+To do the full build, do: `mvn clean install`
+
+
+Building a single module
+====================
+To build a specific module run the command: `mvn clean install` in the module directory
+
+
+Running a Spring Boot module
+====================
+To run a Spring Boot module run the command: `mvn spring-boot:run` in the module directory
+
+
+Working with the IDE
+====================
+This repo contains a large number of modules. 
+When you're working with an individual module, there's no need to import all of them (or build all of them) - you can simply import that particular module in either Eclipse or IntelliJ. 
+
+
+Running Tests
+=============
+The command `mvn clean install` will run the unit tests in a module.
+To run the integration tests, use the command `mvn clean install -Pintegration-lite-first`
+
+
+
+
+

akka-http/README.md

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+## Relevant articles:
+
+- [Introduction to Akka HTTP](https://www.baeldung.com/akka-http)

akka-http/pom.xml

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+<?xml version="1.0"?>
+<project
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
+	xmlns="http://maven.apache.org/POM/4.0.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+
+	<modelVersion>4.0.0</modelVersion>
+	<artifactId>akka-http</artifactId>
+	<name>akka-http</name>
+
+	<parent>
+		<artifactId>parent-modules</artifactId>
+		<groupId>com.baeldung</groupId>
+		<version>1.0.0-SNAPSHOT</version>
+	</parent>
+
+	<dependencies>
+		<dependency>
+			<groupId>com.typesafe.akka</groupId>
+			<artifactId>akka-http_2.12</artifactId>
+			<version>${akka.http.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>com.typesafe.akka</groupId>
+			<artifactId>akka-stream_2.12</artifactId>
+			<version>${akka.stream.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>com.typesafe.akka</groupId>
+			<artifactId>akka-http-jackson_2.12</artifactId>
+			<version>${akka.http.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>com.typesafe.akka</groupId>
+			<artifactId>akka-http-testkit_2.12</artifactId>
+			<version>${akka.http.version}</version>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+		<akka.http.version>10.0.11</akka.http.version>
+		<akka.stream.version>2.5.11</akka.stream.version>
+	</properties>
+</project>

akka-http/src/main/java/com/baeldung/akkahttp/User.java

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+package com.baeldung.akkahttp;
+
+public class User {
+
+    private final Long id;
+
+    private final String name;
+
+    public User() {
+        this.name = "";
+        this.id = null;
+    }
+
+    public User(Long id, String name) {
+        this.name = name;
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public Long getId() {
+        return id;
+    }
+}

akka-http/src/main/java/com/baeldung/akkahttp/UserActor.java

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+package com.baeldung.akkahttp;
+
+import akka.actor.AbstractActor;
+import akka.actor.Props;
+import akka.japi.pf.FI;
+import com.baeldung.akkahttp.UserMessages.ActionPerformed;
+import com.baeldung.akkahttp.UserMessages.CreateUserMessage;
+import com.baeldung.akkahttp.UserMessages.GetUserMessage;
+
+
+class UserActor extends AbstractActor {
+
+  private UserService userService = new UserService();
+
+  static Props props() {
+    return Props.create(UserActor.class);
+  }
+
+  @Override
+  public Receive createReceive() {
+    return receiveBuilder()
+            .match(CreateUserMessage.class, handleCreateUser())
+            .match(GetUserMessage.class, handleGetUser())
+            .build();
+  }
+
+  private FI.UnitApply<CreateUserMessage> handleCreateUser() {
+    return createUserMessageMessage -> {
+      userService.createUser(createUserMessageMessage.getUser());
+      sender().tell(new ActionPerformed(String.format("User %s created.", createUserMessageMessage.getUser()
+              .getName())), getSelf());
+    };
+  }
+
+  private FI.UnitApply<GetUserMessage> handleGetUser() {
+    return getUserMessageMessage -> {
+      sender().tell(userService.getUser(getUserMessageMessage.getUserId()), getSelf());
+    };
+  }
+
+}

akka-http/src/main/java/com/baeldung/akkahttp/UserMessages.java

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+package com.baeldung.akkahttp;
+
+import java.io.Serializable;
+
+public interface UserMessages {
+
+  class ActionPerformed implements Serializable {
+
+    private static final long serialVersionUID = 1L;
+
+    private final String description;
+
+    public ActionPerformed(String description) {
+      this.description = description;
+    }
+
+    public String getDescription() {
+      return description;
+    }
+  }
+
+  class CreateUserMessage implements Serializable {
+
+    private static final long serialVersionUID = 1L;
+    private final User user;
+
+    public CreateUserMessage(User user) {
+      this.user = user;
+    }
+
+    public User getUser() {
+      return user;
+    }
+  }
+
+  class GetUserMessage implements Serializable {
+    private static final long serialVersionUID = 1L;
+    private final Long userId;
+
+    public GetUserMessage(Long userId) {
+      this.userId = userId;
+    }
+
+    public Long getUserId() {
+      return userId;
+    }
+  }
+
+}

akka-http/src/main/java/com/baeldung/akkahttp/UserServer.java

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+package com.baeldung.akkahttp;
+
+import java.util.Optional;
+import java.util.concurrent.CompletionStage;
+import java.util.concurrent.TimeUnit;
+
+import akka.actor.ActorRef;
+import akka.actor.ActorSystem;
+import akka.http.javadsl.marshallers.jackson.Jackson;
+import akka.http.javadsl.model.StatusCodes;
+import akka.http.javadsl.server.HttpApp;
+import akka.http.javadsl.server.Route;
+import akka.pattern.PatternsCS;
+import akka.util.Timeout;
+import com.baeldung.akkahttp.UserMessages.ActionPerformed;
+import com.baeldung.akkahttp.UserMessages.CreateUserMessage;
+import com.baeldung.akkahttp.UserMessages.GetUserMessage;
+import scala.concurrent.duration.Duration;
+import static akka.http.javadsl.server.PathMatchers.*;
+
+class UserServer extends HttpApp {
+
+  private final ActorRef userActor;
+
+  Timeout timeout = new Timeout(Duration.create(5, TimeUnit.SECONDS));
+
+  UserServer(ActorRef userActor) {
+    this.userActor = userActor;
+  }
+
+  @Override
+  public Route routes() {
+    return path("users", this::postUser)
+            .orElse(path(segment("users").slash(longSegment()), id ->
+                    route(getUser(id))));
+  }
+
+  private Route getUser(Long id) {
+    return get(() -> {
+      CompletionStage<Optional<User>> user = PatternsCS.ask(userActor, new GetUserMessage(id), timeout)
+              .thenApply(obj -> (Optional<User>) obj);
+
+      return onSuccess(() -> user, performed -> {
+        if (performed.isPresent())
+          return complete(StatusCodes.OK, performed.get(), Jackson.marshaller());
+        else
+          return complete(StatusCodes.NOT_FOUND);
+      });
+    });
+  }
+
+  private Route postUser() {
+    return route(post(() -> entity(Jackson.unmarshaller(User.class), user -> {
+      CompletionStage<ActionPerformed> userCreated = PatternsCS.ask(userActor, new CreateUserMessage(user), timeout)
+              .thenApply(obj -> (ActionPerformed) obj);
+
+      return onSuccess(() -> userCreated, performed -> {
+        return complete(StatusCodes.CREATED, performed, Jackson.marshaller());
+      });
+    })));
+  }
+
+  public static void main(String[] args) throws Exception {
+    ActorSystem system = ActorSystem.create("userServer");
+    ActorRef userActor = system.actorOf(UserActor.props(), "userActor");
+    UserServer server = new UserServer(userActor);
+    server.startServer("localhost", 8080, system);
+  }
+
+}

akka-http/src/main/java/com/baeldung/akkahttp/UserService.java

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+package com.baeldung.akkahttp;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+
+public class UserService {
+
+  private final static List<User> users = new ArrayList<>();
+
+  static {
+    users.add(new User(1l, "Alice"));
+    users.add(new User(2l, "Bob"));
+    users.add(new User(3l, "Chris"));
+    users.add(new User(4l, "Dick"));
+    users.add(new User(5l, "Eve"));
+    users.add(new User(6l, "Finn"));
+  }
+
+  public Optional<User> getUser(Long id) {
+    return users.stream()
+            .filter(user -> user.getId()
+                    .equals(id))
+            .findFirst();
+  }
+
+  public void createUser(User user) {
+    users.add(user);
+  }
+
+  public List<User> getUsers(){
+    return users;
+  }
+
+}

akka-http/src/test/java/com/baeldung/akkahttp/UserServerUnitTest.java

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+package com.baeldung.akkahttp;
+
+import akka.actor.ActorRef;
+import akka.actor.ActorSystem;
+import akka.http.javadsl.model.ContentTypes;
+import akka.http.javadsl.model.HttpEntities;
+import akka.http.javadsl.model.HttpRequest;
+import akka.http.javadsl.testkit.JUnitRouteTest;
+import akka.http.javadsl.testkit.TestRoute;
+import org.junit.Test;
+
+public class UserServerUnitTest extends JUnitRouteTest {
+
+  ActorSystem system = ActorSystem.create("helloAkkaHttpServer");
+
+  ActorRef userActorRef = system.actorOf(UserActor.props(), "userActor");
+
+  TestRoute appRoute = testRoute(new UserServer(userActorRef).routes());
+
+  @Test
+  public void whenRequest_thenActorResponds() {
+
+    appRoute.run(HttpRequest.GET("/users/1"))
+            .assertEntity(alice())
+            .assertStatusCode(200);
+
+    appRoute.run(HttpRequest.GET("/users/42"))
+            .assertStatusCode(404);
+
+    appRoute.run(HttpRequest.DELETE("/users/1"))
+            .assertStatusCode(200);
+
+    appRoute.run(HttpRequest.DELETE("/users/42"))
+            .assertStatusCode(200);
+
+    appRoute.run(HttpRequest.POST("/users")
+            .withEntity(HttpEntities.create(ContentTypes.APPLICATION_JSON, zaphod())))
+            .assertStatusCode(201);
+
+  }
+
+  private String alice() {
+    return "{\"id\":1,\"name\":\"Alice\"}";
+  }
+
+  private String zaphod() {
+    return "{\"id\":42,\"name\":\"Zaphod\"}";
+  }
+
+}

akka-streams/README.md

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+### Relevant articles
+
+- [Guide to Akka Streams](http://www.baeldung.com/akka-streams)

akka-streams/pom.xml

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>akka-streams</artifactId>
+    <name>akka-streams</name>
+
+    <parent>
+        <artifactId>parent-modules</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.typesafe.akka</groupId>
+            <artifactId>akka-stream_${scala.version}</artifactId>
+            <version>${akkastreams.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.typesafe.akka</groupId>
+            <artifactId>akka-stream-testkit_${scala.version}</artifactId>
+            <version>${akkastreams.version}</version>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <akkastreams.version>2.5.2</akkastreams.version>
+        <scala.version>2.11</scala.version>
+    </properties>
+
+</project>

akka-streams/src/main/java/com/baeldung/akkastreams/AverageRepository.java

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+package com.baeldung.akkastreams;
+
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionStage;
+
+public class AverageRepository {
+    CompletionStage<Double> save(Double average) {
+        return CompletableFuture.supplyAsync(() -> {
+            System.out.println("saving average: " + average);
+            return average;
+        });
+    }
+}

akka-streams/src/main/java/com/baeldung/akkastreams/DataImporter.java

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+package com.baeldung.akkastreams;
+
+
+import akka.Done;
+import akka.NotUsed;
+import akka.actor.ActorSystem;
+import akka.stream.ActorMaterializer;
+import akka.stream.javadsl.Flow;
+import akka.stream.javadsl.Keep;
+import akka.stream.javadsl.Sink;
+import akka.stream.javadsl.Source;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionStage;
+import java.util.stream.Collectors;
+
+public class DataImporter {
+    private final ActorSystem actorSystem;
+    private final AverageRepository averageRepository = new AverageRepository();
+
+    public DataImporter(ActorSystem actorSystem) {
+        this.actorSystem = actorSystem;
+
+    }
+
+    private List<Integer> parseLine(String line) {
+        String[] fields = line.split(";");
+        return Arrays.stream(fields)
+                .map(Integer::parseInt)
+                .collect(Collectors.toList());
+    }
+
+    private Flow<String, Integer, NotUsed> parseContent() {
+        return Flow.of(String.class).mapConcat(this::parseLine);
+    }
+
+    private Flow<Integer, Double, NotUsed> computeAverage() {
+        return Flow.of(Integer.class).grouped(2).mapAsyncUnordered(8, integers ->
+                CompletableFuture.supplyAsync(() -> integers
+                        .stream()
+                        .mapToDouble(v -> v)
+                        .average()
+                        .orElse(-1.0)));
+    }
+
+    Flow<String, Double, NotUsed> calculateAverage() {
+        return Flow.of(String.class)
+                .via(parseContent())
+                .via(computeAverage());
+    }
+
+    private Sink<Double, CompletionStage<Done>> storeAverages() {
+        return Flow.of(Double.class)
+                .mapAsyncUnordered(4, averageRepository::save)
+                .toMat(Sink.ignore(), Keep.right());
+    }
+
+
+    CompletionStage<Done> calculateAverageForContent(String content) {
+        return Source.single(content)
+                .via(calculateAverage())
+                .runWith(storeAverages(), ActorMaterializer.create(actorSystem))
+                .whenComplete((d, e) -> {
+                    if (d != null) {
+                        System.out.println("Import finished ");
+                    } else {
+                        e.printStackTrace();
+                    }
+                });
+    }
+
+}

akka-streams/src/main/resources/logback.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

akka-streams/src/test/java/com/baeldung/akkastreams/DataImporterUnitTest.java

@@ -0,0 +1,43 @@
+package com.baeldung.akkastreams;
+
+import akka.NotUsed;
+import akka.actor.ActorSystem;
+import akka.stream.ActorMaterializer;
+import akka.stream.javadsl.Flow;
+import akka.stream.javadsl.Source;
+import akka.stream.testkit.javadsl.TestSink;
+import org.junit.Test;
+
+
+public class DataImporterUnitTest {
+    private final ActorSystem actorSystem = ActorSystem.create();
+
+    @Test
+    public void givenStreamOfIntegers_whenCalculateAverageOfPairs_thenShouldReturnProperResults() {
+        //given
+        Flow<String, Double, NotUsed> tested = new DataImporter(actorSystem).calculateAverage();
+        String input = "1;9;11;0";
+
+        //when
+        Source<Double, NotUsed> flow = Source.single(input).via(tested);
+
+        //then
+        flow
+                .runWith(TestSink.probe(actorSystem), ActorMaterializer.create(actorSystem))
+                .request(4)
+                .expectNextUnordered(5d, 5.5);
+    }
+
+    @Test
+    public void givenStreamOfIntegers_whenCalculateAverageAndSaveToSink_thenShouldFinishSuccessfully() {
+        //given
+        DataImporter dataImporter = new DataImporter(actorSystem);
+        String input = "10;90;110;10";
+
+        //when
+        dataImporter.calculateAverageForContent(input)
+                .thenAccept(d -> actorSystem.terminate());
+
+    }
+
+}

algorithms-genetic/.gitignore

@@ -0,0 +1,4 @@
+/target/
+.settings/
+.classpath
+.project

algorithms-genetic/README.md

@@ -0,0 +1,6 @@
+## Relevant articles:
+
+- [Introduction to Jenetics Library](http://www.baeldung.com/jenetics)
+- [Ant Colony Optimization](http://www.baeldung.com/java-ant-colony-optimization)
+- [Design a Genetic Algorithm in Java](https://www.baeldung.com/java-genetic-algorithm)
+- [The Traveling Salesman Problem in Java](https://www.baeldung.com/java-simulated-annealing-for-traveling-salesman)

algorithms-genetic/pom.xml

@@ -0,0 +1,64 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>algorithms-genetic</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>algorithms-genetic</name>
+    
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-math3</artifactId>
+            <version>${commons-math3.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>commons-codec</groupId>
+            <artifactId>commons-codec</artifactId>
+            <version>${commons-codec.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>${lombok.version}</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.jenetics</groupId>
+            <artifactId>jenetics</artifactId>
+            <version>${io.jenetics.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${org.assertj.core.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>org.codehaus.mojo</groupId>
+                    <artifactId>exec-maven-plugin</artifactId>
+                    <version>${exec-maven-plugin.version}</version>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+
+    <properties>
+        <commons-math3.version>3.6.1</commons-math3.version>
+        <io.jenetics.version>3.7.0</io.jenetics.version>
+        <org.assertj.core.version>3.9.0</org.assertj.core.version>
+        <commons-codec.version>1.11</commons-codec.version>
+    </properties>
+
+    
+</project>

algorithms-genetic/src/main/java/com/baeldung/algorithms/RunAlgorithm.java

@@ -0,0 +1,38 @@
+package com.baeldung.algorithms;
+
+import java.util.Scanner;
+
+import com.baeldung.algorithms.ga.annealing.SimulatedAnnealing;
+import com.baeldung.algorithms.ga.ant_colony.AntColonyOptimization;
+import com.baeldung.algorithms.ga.binary.SimpleGeneticAlgorithm;
+
+public class RunAlgorithm {
+
+	public static void main(String[] args) throws InstantiationException, IllegalAccessException {
+		Scanner in = new Scanner(System.in);
+		System.out.println("Run algorithm:");
+		System.out.println("1 - Simulated Annealing");
+		System.out.println("2 - Simple Genetic Algorithm");
+		System.out.println("3 - Ant Colony");
+		int decision = in.nextInt();
+		switch (decision) {
+		case 1:
+			System.out.println(
+					"Optimized distance for travel: " + SimulatedAnnealing.simulateAnnealing(10, 10000, 0.9995));
+			break;
+		case 2:
+			SimpleGeneticAlgorithm ga = new SimpleGeneticAlgorithm();
+			ga.runAlgorithm(50, "1011000100000100010000100000100111001000000100000100000000001111");
+			break;
+		case 3:
+			AntColonyOptimization antColony = new AntColonyOptimization(21);
+			antColony.startAntOptimization();
+			break;
+		default:
+			System.out.println("Unknown option");
+			break;
+		}
+		in.close();
+	}
+
+}

algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/annealing/City.java

@@ -0,0 +1,22 @@
+package com.baeldung.algorithms.ga.annealing;
+
+import lombok.Data;
+
+@Data
+public class City {
+
+    private int x;
+    private int y;
+
+    public City() {
+        this.x = (int) (Math.random() * 500);
+        this.y = (int) (Math.random() * 500);
+    }
+
+    public double distanceToCity(City city) {
+        int x = Math.abs(getX() - city.getX());
+        int y = Math.abs(getY() - city.getY());
+        return Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2));
+    }
+
+}

algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/annealing/SimulatedAnnealing.java

@@ -0,0 +1,36 @@
+package com.baeldung.algorithms.ga.annealing;
+
+public class SimulatedAnnealing {
+
+    private static Travel travel = new Travel(10);
+
+    public static double simulateAnnealing(double startingTemperature, int numberOfIterations, double coolingRate) {
+        System.out.println("Starting SA with temperature: " + startingTemperature + ", # of iterations: " + numberOfIterations + " and colling rate: " + coolingRate);
+        double t = startingTemperature;
+        travel.generateInitialTravel();
+        double bestDistance = travel.getDistance();
+        System.out.println("Initial distance of travel: " + bestDistance);
+        Travel bestSolution = travel;
+        Travel currentSolution = bestSolution;
+
+        for (int i = 0; i < numberOfIterations; i++) {
+            if (t > 0.1) {
+                currentSolution.swapCities();
+                double currentDistance = currentSolution.getDistance();
+                if (currentDistance < bestDistance) {
+                    bestDistance = currentDistance;
+                } else if (Math.exp((bestDistance - currentDistance) / t) < Math.random()) {
+                    currentSolution.revertSwap();
+                }
+                t *= coolingRate;
+            } else {
+                continue;
+            }
+            if (i % 100 == 0) {
+                System.out.println("Iteration #" + i);
+            }
+        }
+        return bestDistance;
+    }
+
+}

algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/annealing/Travel.java

@@ -0,0 +1,63 @@
+package com.baeldung.algorithms.ga.annealing;
+
+import java.util.ArrayList;
+import java.util.Collections;
+
+import lombok.Data;
+
+@Data
+public class Travel {
+
+    private ArrayList<City> travel = new ArrayList<>();
+    private ArrayList<City> previousTravel = new ArrayList<>();
+
+    public Travel(int numberOfCities) {
+        for (int i = 0; i < numberOfCities; i++) {
+            travel.add(new City());
+        }
+    }
+
+    public void generateInitialTravel() {
+        if (travel.isEmpty())
+            new Travel(10);
+        Collections.shuffle(travel);
+    }
+
+    public void swapCities() {
+        int a = generateRandomIndex();
+        int b = generateRandomIndex();
+        previousTravel = travel;
+        City x = travel.get(a);
+        City y = travel.get(b);
+        travel.set(a, y);
+        travel.set(b, x);
+    }
+
+    public void revertSwap() {
+        travel = previousTravel;
+    }
+
+    private int generateRandomIndex() {
+        return (int) (Math.random() * travel.size());
+    }
+
+    public City getCity(int index) {
+        return travel.get(index);
+    }
+
+    public int getDistance() {
+        int distance = 0;
+        for (int index = 0; index < travel.size(); index++) {
+            City starting = getCity(index);
+            City destination;
+            if (index + 1 < travel.size()) {
+                destination = getCity(index + 1);
+            } else {
+                destination = getCity(0);
+            }
+            distance += starting.distanceToCity(destination);
+        }
+        return distance;
+    }
+
+}

algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/ant_colony/Ant.java

@@ -0,0 +1,37 @@
+package com.baeldung.algorithms.ga.ant_colony;
+
+public class Ant {
+
+	protected int trailSize;
+	protected int trail[];
+	protected boolean visited[];
+
+	public Ant(int tourSize) {
+		this.trailSize = tourSize;
+		this.trail = new int[tourSize];
+		this.visited = new boolean[tourSize];
+	}
+
+	protected void visitCity(int currentIndex, int city) {
+		trail[currentIndex + 1] = city;
+		visited[city] = true;
+	}
+
+	protected boolean visited(int i) {
+		return visited[i];
+	}
+
+	protected double trailLength(double graph[][]) {
+		double length = graph[trail[trailSize - 1]][trail[0]];
+		for (int i = 0; i < trailSize - 1; i++) {
+			length += graph[trail[i]][trail[i + 1]];
+		}
+		return length;
+	}
+
+	protected void clear() {
+		for (int i = 0; i < trailSize; i++)
+			visited[i] = false;
+	}
+
+}

algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/ant_colony/AntColonyOptimization.java

@@ -0,0 +1,203 @@
+package com.baeldung.algorithms.ga.ant_colony;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.OptionalInt;
+import java.util.Random;
+import java.util.stream.IntStream;
+
+public class AntColonyOptimization {
+
+    private double c = 1.0;
+    private double alpha = 1;
+    private double beta = 5;
+    private double evaporation = 0.5;
+    private double Q = 500;
+    private double antFactor = 0.8;
+    private double randomFactor = 0.01;
+
+    private int maxIterations = 1000;
+
+    private int numberOfCities;
+    private int numberOfAnts;
+    private double graph[][];
+    private double trails[][];
+    private List<Ant> ants = new ArrayList<>();
+    private Random random = new Random();
+    private double probabilities[];
+
+    private int currentIndex;
+
+    private int[] bestTourOrder;
+    private double bestTourLength;
+
+    public AntColonyOptimization(int noOfCities) {
+        graph = generateRandomMatrix(noOfCities);
+        numberOfCities = graph.length;
+        numberOfAnts = (int) (numberOfCities * antFactor);
+
+        trails = new double[numberOfCities][numberOfCities];
+        probabilities = new double[numberOfCities];
+        IntStream.range(0, numberOfAnts)
+            .forEach(i -> ants.add(new Ant(numberOfCities)));
+    }
+
+    /**
+     * Generate initial solution
+     */
+    public double[][] generateRandomMatrix(int n) {
+        double[][] randomMatrix = new double[n][n];
+        IntStream.range(0, n)
+            .forEach(i -> IntStream.range(0, n)
+                .forEach(j -> randomMatrix[i][j] = Math.abs(random.nextInt(100) + 1)));
+        return randomMatrix;
+    }
+
+    /**
+     * Perform ant optimization
+     */
+    public void startAntOptimization() {
+        IntStream.rangeClosed(1, 3)
+            .forEach(i -> {
+                System.out.println("Attempt #" + i);
+                solve();
+            });
+    }
+
+    /**
+     * Use this method to run the main logic
+     */
+    public int[] solve() {
+        setupAnts();
+        clearTrails();
+        IntStream.range(0, maxIterations)
+            .forEach(i -> {
+                moveAnts();
+                updateTrails();
+                updateBest();
+            });
+        System.out.println("Best tour length: " + (bestTourLength - numberOfCities));
+        System.out.println("Best tour order: " + Arrays.toString(bestTourOrder));
+        return bestTourOrder.clone();
+    }
+
+    /**
+     * Prepare ants for the simulation
+     */
+    private void setupAnts() {
+        IntStream.range(0, numberOfAnts)
+            .forEach(i -> {
+                ants.forEach(ant -> {
+                    ant.clear();
+                    ant.visitCity(-1, random.nextInt(numberOfCities));
+                });
+            });
+        currentIndex = 0;
+    }
+
+    /**
+     * At each iteration, move ants
+     */
+    private void moveAnts() {
+        IntStream.range(currentIndex, numberOfCities - 1)
+            .forEach(i -> {
+                ants.forEach(ant -> ant.visitCity(currentIndex, selectNextCity(ant)));
+                currentIndex++;
+            });
+    }
+
+    /**
+     * Select next city for each ant
+     */
+    private int selectNextCity(Ant ant) {
+        int t = random.nextInt(numberOfCities - currentIndex);
+        if (random.nextDouble() < randomFactor) {
+            OptionalInt cityIndex = IntStream.range(0, numberOfCities)
+                .filter(i -> i == t && !ant.visited(i))
+                .findFirst();
+            if (cityIndex.isPresent()) {
+                return cityIndex.getAsInt();
+            }
+        }
+        calculateProbabilities(ant);
+        double r = random.nextDouble();
+        double total = 0;
+        for (int i = 0; i < numberOfCities; i++) {
+            total += probabilities[i];
+            if (total >= r) {
+                return i;
+            }
+        }
+
+        throw new RuntimeException("There are no other cities");
+    }
+
+    /**
+     * Calculate the next city picks probabilites
+     */
+    public void calculateProbabilities(Ant ant) {
+        int i = ant.trail[currentIndex];
+        double pheromone = 0.0;
+        for (int l = 0; l < numberOfCities; l++) {
+            if (!ant.visited(l)) {
+                pheromone += Math.pow(trails[i][l], alpha) * Math.pow(1.0 / graph[i][l], beta);
+            }
+        }
+        for (int j = 0; j < numberOfCities; j++) {
+            if (ant.visited(j)) {
+                probabilities[j] = 0.0;
+            } else {
+                double numerator = Math.pow(trails[i][j], alpha) * Math.pow(1.0 / graph[i][j], beta);
+                probabilities[j] = numerator / pheromone;
+            }
+        }
+    }
+
+    /**
+     * Update trails that ants used
+     */
+    private void updateTrails() {
+        for (int i = 0; i < numberOfCities; i++) {
+            for (int j = 0; j < numberOfCities; j++) {
+                trails[i][j] *= evaporation;
+            }
+        }
+        for (Ant a : ants) {
+            double contribution = Q / a.trailLength(graph);
+            for (int i = 0; i < numberOfCities - 1; i++) {
+                trails[a.trail[i]][a.trail[i + 1]] += contribution;
+            }
+            trails[a.trail[numberOfCities - 1]][a.trail[0]] += contribution;
+        }
+    }
+
+    /**
+     * Update the best solution
+     */
+    private void updateBest() {
+        if (bestTourOrder == null) {
+            bestTourOrder = ants.get(0).trail;
+            bestTourLength = ants.get(0)
+                .trailLength(graph);
+        }
+        for (Ant a : ants) {
+            if (a.trailLength(graph) < bestTourLength) {
+                bestTourLength = a.trailLength(graph);
+                bestTourOrder = a.trail.clone();
+            }
+        }
+    }
+
+    /**
+     * Clear trails after simulation
+     */
+    private void clearTrails() {
+        IntStream.range(0, numberOfCities)
+            .forEach(i -> {
+                IntStream.range(0, numberOfCities)
+                    .forEach(j -> trails[i][j] = c);
+            });
+    }
+
+}

algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/binary/Individual.java

@@ -0,0 +1,44 @@
+package com.baeldung.algorithms.ga.binary;
+
+import lombok.Data;
+
+@Data
+public class Individual {
+
+    protected int defaultGeneLength = 64;
+    private byte[] genes = new byte[defaultGeneLength];
+    private int fitness = 0;
+
+    public Individual() {
+        for (int i = 0; i < genes.length; i++) {
+            byte gene = (byte) Math.round(Math.random());
+            genes[i] = gene;
+        }
+    }
+
+    protected byte getSingleGene(int index) {
+        return genes[index];
+    }
+
+    protected void setSingleGene(int index, byte value) {
+        genes[index] = value;
+        fitness = 0;
+    }
+
+    public int getFitness() {
+        if (fitness == 0) {
+            fitness = SimpleGeneticAlgorithm.getFitness(this);
+        }
+        return fitness;
+    }
+
+    @Override
+    public String toString() {
+        String geneString = "";
+        for (int i = 0; i < genes.length; i++) {
+            geneString += getSingleGene(i);
+        }
+        return geneString;
+    }
+
+}

algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/binary/Population.java

@@ -0,0 +1,40 @@
+package com.baeldung.algorithms.ga.binary;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import lombok.Data;
+
+@Data
+public class Population {
+
+    private List<Individual> individuals;
+
+    public Population(int size, boolean createNew) {
+        individuals = new ArrayList<>();
+        if (createNew) {
+            createNewPopulation(size);
+        }
+    }
+
+    protected Individual getIndividual(int index) {
+        return individuals.get(index);
+    }
+
+    protected Individual getFittest() {
+        Individual fittest = individuals.get(0);
+        for (int i = 0; i < individuals.size(); i++) {
+            if (fittest.getFitness() <= getIndividual(i).getFitness()) {
+                fittest = getIndividual(i);
+            }
+        }
+        return fittest;
+    }
+
+    private void createNewPopulation(int size) {
+        for (int i = 0; i < size; i++) {
+            Individual newIndividual = new Individual();
+            individuals.add(i, newIndividual);
+        }
+    }
+}

algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/binary/SimpleGeneticAlgorithm.java

@@ -0,0 +1,117 @@
+package com.baeldung.algorithms.ga.binary;
+
+import lombok.Data;
+
+@Data
+public class SimpleGeneticAlgorithm {
+
+    private static final double uniformRate = 0.5;
+    private static final double mutationRate = 0.025;
+    private static final int tournamentSize = 5;
+    private static final boolean elitism = true;
+    private static byte[] solution = new byte[64];
+
+    public boolean runAlgorithm(int populationSize, String solution) {
+        if (solution.length() != SimpleGeneticAlgorithm.solution.length) {
+            throw new RuntimeException("The solution needs to have " + SimpleGeneticAlgorithm.solution.length + " bytes");
+        }
+        setSolution(solution);
+        Population myPop = new Population(populationSize, true);
+
+        int generationCount = 1;
+        while (myPop.getFittest().getFitness() < getMaxFitness()) {
+            System.out.println("Generation: " + generationCount + " Correct genes found: " + myPop.getFittest().getFitness());
+            myPop = evolvePopulation(myPop);
+            generationCount++;
+        }
+        System.out.println("Solution found!");
+        System.out.println("Generation: " + generationCount);
+        System.out.println("Genes: ");
+        System.out.println(myPop.getFittest());
+        return true;
+    }
+
+    public Population evolvePopulation(Population pop) {
+        int elitismOffset;
+        Population newPopulation = new Population(pop.getIndividuals().size(), false);
+
+        if (elitism) {
+            newPopulation.getIndividuals().add(0, pop.getFittest());
+            elitismOffset = 1;
+        } else {
+            elitismOffset = 0;
+        }
+
+        for (int i = elitismOffset; i < pop.getIndividuals().size(); i++) {
+            Individual indiv1 = tournamentSelection(pop);
+            Individual indiv2 = tournamentSelection(pop);
+            Individual newIndiv = crossover(indiv1, indiv2);
+            newPopulation.getIndividuals().add(i, newIndiv);
+        }
+
+        for (int i = elitismOffset; i < newPopulation.getIndividuals().size(); i++) {
+            mutate(newPopulation.getIndividual(i));
+        }
+
+        return newPopulation;
+    }
+
+    private Individual crossover(Individual indiv1, Individual indiv2) {
+        Individual newSol = new Individual();
+        for (int i = 0; i < newSol.getDefaultGeneLength(); i++) {
+            if (Math.random() <= uniformRate) {
+                newSol.setSingleGene(i, indiv1.getSingleGene(i));
+            } else {
+                newSol.setSingleGene(i, indiv2.getSingleGene(i));
+            }
+        }
+        return newSol;
+    }
+
+    private void mutate(Individual indiv) {
+        for (int i = 0; i < indiv.getDefaultGeneLength(); i++) {
+            if (Math.random() <= mutationRate) {
+                byte gene = (byte) Math.round(Math.random());
+                indiv.setSingleGene(i, gene);
+            }
+        }
+    }
+
+    private Individual tournamentSelection(Population pop) {
+        Population tournament = new Population(tournamentSize, false);
+        for (int i = 0; i < tournamentSize; i++) {
+            int randomId = (int) (Math.random() * pop.getIndividuals().size());
+            tournament.getIndividuals().add(i, pop.getIndividual(randomId));
+        }
+        Individual fittest = tournament.getFittest();
+        return fittest;
+    }
+
+    protected static int getFitness(Individual individual) {
+        int fitness = 0;
+        for (int i = 0; i < individual.getDefaultGeneLength() && i < solution.length; i++) {
+            if (individual.getSingleGene(i) == solution[i]) {
+                fitness++;
+            }
+        }
+        return fitness;
+    }
+
+    protected int getMaxFitness() {
+        int maxFitness = solution.length;
+        return maxFitness;
+    }
+
+    protected void setSolution(String newSolution) {
+        solution = new byte[newSolution.length()];
+        for (int i = 0; i < newSolution.length(); i++) {
+            String character = newSolution.substring(i, i + 1);
+            if (character.contains("0") || character.contains("1")) {
+                solution[i] = Byte.parseByte(character);
+            } else {
+                solution[i] = 0;
+            }
+        }
+    }
+
+}

algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/jenetics/Knapsack.java

@@ -0,0 +1,47 @@
+package com.baeldung.algorithms.ga.jenetics;
+
+import static org.jenetics.engine.EvolutionResult.toBestPhenotype;
+import static org.jenetics.engine.limit.bySteadyFitness;
+
+import java.util.stream.Stream;
+
+import org.jenetics.BitChromosome;
+import org.jenetics.BitGene;
+import org.jenetics.Mutator;
+import org.jenetics.Phenotype;
+import org.jenetics.RouletteWheelSelector;
+import org.jenetics.SinglePointCrossover;
+import org.jenetics.TournamentSelector;
+import org.jenetics.engine.Engine;
+import org.jenetics.engine.EvolutionStatistics;
+
+//The main class.
+public class Knapsack {
+
+    public static void main(String[] args) {
+        int nItems = 15;
+        double ksSize = nItems * 100.0 / 3.0;
+
+        KnapsackFF ff = new KnapsackFF(Stream.generate(KnapsackItem::random)
+            .limit(nItems)
+            .toArray(KnapsackItem[]::new), ksSize);
+
+        Engine<BitGene, Double> engine = Engine.builder(ff, BitChromosome.of(nItems, 0.5))
+            .populationSize(500)
+            .survivorsSelector(new TournamentSelector<>(5))
+            .offspringSelector(new RouletteWheelSelector<>())
+            .alterers(new Mutator<>(0.115), new SinglePointCrossover<>(0.16))
+            .build();
+
+        EvolutionStatistics<Double, ?> statistics = EvolutionStatistics.ofNumber();
+
+        Phenotype<BitGene, Double> best = engine.stream()
+            .limit(bySteadyFitness(7))
+            .limit(100)
+            .peek(statistics)
+            .collect(toBestPhenotype());
+
+        System.out.println(statistics);
+        System.out.println(best);
+    }
+}

algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/jenetics/KnapsackFF.java

@@ -0,0 +1,25 @@
+package com.baeldung.algorithms.ga.jenetics;
+
+import java.util.function.Function;
+
+import org.jenetics.BitChromosome;
+import org.jenetics.BitGene;
+import org.jenetics.Genotype;
+
+public class KnapsackFF implements Function<Genotype<BitGene>, Double> {
+    private KnapsackItem[] items;
+    private double size;
+
+    public KnapsackFF(KnapsackItem[] items, double size) {
+        this.items = items;
+        this.size = size;
+    }
+
+    @Override
+    public Double apply(Genotype<BitGene> gt) {
+        KnapsackItem sum = ((BitChromosome) gt.getChromosome()).ones()
+            .mapToObj(i -> items[i])
+            .collect(KnapsackItem.toSum());
+        return sum.size <= this.size ? sum.value : 0;
+    }
+}

algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/jenetics/KnapsackItem.java

@@ -0,0 +1,34 @@
+package com.baeldung.algorithms.ga.jenetics;
+
+import java.util.Random;
+import java.util.stream.Collector;
+
+import org.jenetics.util.RandomRegistry;
+
+public class KnapsackItem {
+
+    public double size;
+    public double value;
+
+    public KnapsackItem(double size, double value) {
+        this.size = size;
+        this.value = value;
+    }
+
+    protected static KnapsackItem random() {
+        Random r = RandomRegistry.getRandom();
+        return new KnapsackItem(r.nextDouble() * 100, r.nextDouble() * 100);
+    }
+
+    protected static Collector<KnapsackItem, ?, KnapsackItem> toSum() {
+        return Collector.of(() -> new double[2], (a, b) -> {
+            a[0] += b.size;
+            a[1] += b.value;
+        } , (a, b) -> {
+            a[0] += b[0];
+            a[1] += b[1];
+            return a;
+        } , r -> new KnapsackItem(r[0], r[1]));
+    }
+
+}

algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/jenetics/SimpleGeneticAlgorithm.java

@@ -0,0 +1,33 @@
+package com.baeldung.algorithms.ga.jenetics;
+
+import org.jenetics.BitChromosome;
+import org.jenetics.BitGene;
+import org.jenetics.Genotype;
+import org.jenetics.engine.Engine;
+import org.jenetics.engine.EvolutionResult;
+import org.jenetics.util.Factory;
+
+public class SimpleGeneticAlgorithm {
+
+    private static Integer eval(Genotype<BitGene> gt) {
+        return gt.getChromosome()
+            .as(BitChromosome.class)
+            .bitCount();
+    }
+
+    public static void main(String[] args) {
+        Factory<Genotype<BitGene>> gtf = Genotype.of(BitChromosome.of(10, 0.5));
+        System.out.println("Before the evolution:\n" + gtf);
+
+        Engine<BitGene, Integer> engine = Engine.builder(SimpleGeneticAlgorithm::eval, gtf)
+            .build();
+
+        Genotype<BitGene> result = engine.stream()
+            .limit(500)
+            .collect(EvolutionResult.toBestGenotype());
+
+        System.out.println("After the evolution:\n" + result);
+
+    }
+
+}

algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/jenetics/SpringsteenProblem.java

@@ -0,0 +1,86 @@
+package com.baeldung.algorithms.ga.jenetics;
+
+import static java.util.Objects.requireNonNull;
+
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+import org.jenetics.BitGene;
+import org.jenetics.engine.Codec;
+import org.jenetics.engine.Engine;
+import org.jenetics.engine.EvolutionResult;
+import org.jenetics.engine.Problem;
+import org.jenetics.engine.codecs;
+import org.jenetics.util.ISeq;
+
+public class SpringsteenProblem implements Problem<ISeq<SpringsteenRecord>, BitGene, Double> {
+
+    private ISeq<SpringsteenRecord> records;
+    private double maxPricePerUniqueSong;
+
+    public SpringsteenProblem(ISeq<SpringsteenRecord> records, double maxPricePerUniqueSong) {
+        this.records = requireNonNull(records);
+        this.maxPricePerUniqueSong = maxPricePerUniqueSong;
+    }
+
+    @Override
+    public Function<ISeq<SpringsteenRecord>, Double> fitness() {
+        return SpringsteenRecords -> {
+            double cost = SpringsteenRecords.stream()
+                .mapToDouble(r -> r.price)
+                .sum();
+
+            int uniqueSongCount = SpringsteenRecords.stream()
+                .flatMap(r -> r.songs.stream())
+                .collect(Collectors.toSet())
+                .size();
+
+            double pricePerUniqueSong = cost / uniqueSongCount;
+
+            return pricePerUniqueSong <= maxPricePerUniqueSong ? uniqueSongCount : 0.0;
+        };
+    }
+
+    @Override
+    public Codec<ISeq<SpringsteenRecord>, BitGene> codec() {
+        return codecs.ofSubSet(records);
+    }
+
+    public static void main(String[] args) {
+        double maxPricePerUniqueSong = 2.5;
+
+        SpringsteenProblem springsteen = new SpringsteenProblem(
+            ISeq.of(new SpringsteenRecord("SpringsteenRecord1", 25, ISeq.of("Song1", "Song2", "Song3", "Song4", "Song5", "Song6")), new SpringsteenRecord("SpringsteenRecord2", 15, ISeq.of("Song2", "Song3", "Song4", "Song5", "Song6", "Song7")),
+                new SpringsteenRecord("SpringsteenRecord3", 35, ISeq.of("Song5", "Song6", "Song7", "Song8", "Song9", "Song10")), new SpringsteenRecord("SpringsteenRecord4", 17, ISeq.of("Song9", "Song10", "Song12", "Song4", "Song13", "Song14")),
+                new SpringsteenRecord("SpringsteenRecord5", 29, ISeq.of("Song1", "Song2", "Song13", "Song14", "Song15", "Song16")), new SpringsteenRecord("SpringsteenRecord6", 5, ISeq.of("Song18", "Song20", "Song30", "Song40"))),
+            maxPricePerUniqueSong);
+
+        Engine<BitGene, Double> engine = Engine.builder(springsteen)
+            .build();
+
+        ISeq<SpringsteenRecord> result = springsteen.codec()
+            .decoder()
+            .apply(engine.stream()
+                .limit(10)
+                .collect(EvolutionResult.toBestGenotype()));
+
+        double cost = result.stream()
+            .mapToDouble(r -> r.price)
+            .sum();
+
+        int uniqueSongCount = result.stream()
+            .flatMap(r -> r.songs.stream())
+            .collect(Collectors.toSet())
+            .size();
+
+        double pricePerUniqueSong = cost / uniqueSongCount;
+
+        System.out.println("Overall cost:  " + cost);
+        System.out.println("Unique songs:  " + uniqueSongCount);
+        System.out.println("Cost per song: " + pricePerUniqueSong);
+        System.out.println("Records:       " + result.map(r -> r.name)
+            .toString(", "));
+
+    }
+
+}

algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/jenetics/SpringsteenRecord.java

@@ -0,0 +1,24 @@
+package com.baeldung.algorithms.ga.jenetics;
+
+import static java.util.Objects.requireNonNull;
+
+import org.jenetics.util.ISeq;
+
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@NoArgsConstructor
+public class SpringsteenRecord {
+
+    String name;
+    double price;
+    ISeq<String> songs;
+
+    public SpringsteenRecord(String name, double price, ISeq<String> songs) {
+        this.name = requireNonNull(name);
+        this.price = price;
+        this.songs = requireNonNull(songs);
+    }
+
+}

algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/jenetics/SubsetSum.java

@@ -0,0 +1,66 @@
+package com.baeldung.algorithms.ga.jenetics;
+
+import static java.util.Objects.requireNonNull;
+
+import java.util.Random;
+import java.util.function.Function;
+
+import org.jenetics.EnumGene;
+import org.jenetics.Mutator;
+import org.jenetics.PartiallyMatchedCrossover;
+import org.jenetics.Phenotype;
+import org.jenetics.engine.Codec;
+import org.jenetics.engine.Engine;
+import org.jenetics.engine.EvolutionResult;
+import org.jenetics.engine.Problem;
+import org.jenetics.engine.codecs;
+import org.jenetics.engine.limit;
+import org.jenetics.util.ISeq;
+import org.jenetics.util.LCG64ShiftRandom;
+
+public class SubsetSum implements Problem<ISeq<Integer>, EnumGene<Integer>, Integer> {
+
+    private ISeq<Integer> basicSet;
+    private int size;
+
+    public SubsetSum(ISeq<Integer> basicSet, int size) {
+        this.basicSet = requireNonNull(basicSet);
+        this.size = size;
+    }
+
+    @Override
+    public Function<ISeq<Integer>, Integer> fitness() {
+        return subset -> Math.abs(subset.stream()
+            .mapToInt(Integer::intValue)
+            .sum());
+    }
+
+    @Override
+    public Codec<ISeq<Integer>, EnumGene<Integer>> codec() {
+        return codecs.ofSubSet(basicSet, size);
+    }
+
+    public static SubsetSum of(int n, int k, Random random) {
+        return new SubsetSum(random.doubles()
+            .limit(n)
+            .mapToObj(d -> (int) ((d - 0.5) * n))
+            .collect(ISeq.toISeq()), k);
+    }
+
+    public static void main(String[] args) {
+        SubsetSum problem = of(500, 15, new LCG64ShiftRandom(101010));
+
+        Engine<EnumGene<Integer>, Integer> engine = Engine.builder(problem)
+            .minimizing()
+            .maximalPhenotypeAge(5)
+            .alterers(new PartiallyMatchedCrossover<>(0.4), new Mutator<>(0.3))
+            .build();
+
+        Phenotype<EnumGene<Integer>, Integer> result = engine.stream()
+            .limit(limit.bySteadyFitness(55))
+            .collect(EvolutionResult.toBestPhenotype());
+
+        System.out.print(result);
+    }
+
+}

algorithms-genetic/src/main/java/com/baeldung/algorithms/ga/jenetics/TravelingSalesman.java

@@ -0,0 +1,67 @@
+package com.baeldung.algorithms.ga.jenetics;
+
+import static java.lang.Math.PI;
+import static java.lang.Math.abs;
+import static java.lang.Math.sin;
+import static org.jenetics.engine.EvolutionResult.toBestPhenotype;
+import static org.jenetics.engine.limit.bySteadyFitness;
+
+import java.util.stream.IntStream;
+
+import org.jenetics.EnumGene;
+import org.jenetics.Optimize;
+import org.jenetics.PartiallyMatchedCrossover;
+import org.jenetics.Phenotype;
+import org.jenetics.SwapMutator;
+import org.jenetics.engine.Engine;
+import org.jenetics.engine.EvolutionStatistics;
+import org.jenetics.engine.codecs;
+
+public class TravelingSalesman {
+
+    private static final int STOPS = 50;
+    private static final double[][] ADJACENCE = matrix(STOPS);
+
+    private static double[][] matrix(int stops) {
+        final double radius = 100.0;
+        double[][] matrix = new double[stops][stops];
+
+        for (int i = 0; i < stops; ++i) {
+            for (int j = 0; j < stops; ++j) {
+                matrix[i][j] = chord(stops, abs(i - j), radius);
+            }
+        }
+        return matrix;
+    }
+
+    private static double chord(int stops, int i, double r) {
+        return 2.0 * r * abs(sin(PI * i / stops));
+    }
+
+    private static double dist(final int[] path) {
+        return IntStream.range(0, STOPS)
+            .mapToDouble(i -> ADJACENCE[path[i]][path[(i + 1) % STOPS]])
+            .sum();
+    }
+
+    public static void main(String[] args) {
+        final Engine<EnumGene<Integer>, Double> engine = Engine.builder(TravelingSalesman::dist, codecs.ofPermutation(STOPS))
+            .optimize(Optimize.MINIMUM)
+            .maximalPhenotypeAge(11)
+            .populationSize(500)
+            .alterers(new SwapMutator<>(0.2), new PartiallyMatchedCrossover<>(0.35))
+            .build();
+
+        final EvolutionStatistics<Double, ?> statistics = EvolutionStatistics.ofNumber();
+
+        final Phenotype<EnumGene<Integer>, Double> best = engine.stream()
+            .limit(bySteadyFitness(15))
+            .limit(250)
+            .peek(statistics)
+            .collect(toBestPhenotype());
+
+        System.out.println(statistics);
+        System.out.println(best);
+    }
+
+}

algorithms-genetic/src/main/resources/logback.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

algorithms-genetic/src/test/java/com/baeldung/algorithms/AntColonyOptimizationLongRunningUnitTest.java

@@ -0,0 +1,22 @@
+package com.baeldung.algorithms;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import com.baeldung.algorithms.ga.ant_colony.AntColonyOptimization;
+
+public class AntColonyOptimizationLongRunningUnitTest {
+
+    @Test
+    public void testGenerateRandomMatrix() {
+        AntColonyOptimization antTSP = new AntColonyOptimization(5);
+        Assert.assertNotNull(antTSP.generateRandomMatrix(5));
+    }
+
+    @Test
+    public void testStartAntOptimization() {
+        AntColonyOptimization antTSP = new AntColonyOptimization(5);
+        Assert.assertNotNull(antTSP.solve());
+    }
+
+}

algorithms-genetic/src/test/java/com/baeldung/algorithms/BinaryGeneticAlgorithmLongRunningUnitTest.java

@@ -0,0 +1,16 @@
+package com.baeldung.algorithms;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import com.baeldung.algorithms.ga.binary.SimpleGeneticAlgorithm;
+
+public class BinaryGeneticAlgorithmLongRunningUnitTest {
+
+    @Test
+    public void testGA() {
+        SimpleGeneticAlgorithm ga = new SimpleGeneticAlgorithm();
+        Assert.assertTrue(ga.runAlgorithm(50, "1011000100000100010000100000100111001000000100000100000000001111"));
+    }
+
+}

algorithms-genetic/src/test/java/com/baeldung/algorithms/SimulatedAnnealingLongRunningUnitTest.java

@@ -0,0 +1,15 @@
+package com.baeldung.algorithms;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import com.baeldung.algorithms.ga.annealing.SimulatedAnnealing;
+
+public class SimulatedAnnealingLongRunningUnitTest {
+
+    @Test
+    public void testSimulateAnnealing() {
+        Assert.assertTrue(SimulatedAnnealing.simulateAnnealing(10, 1000, 0.9) > 0);
+    }
+
+}

algorithms-miscellaneous-1/.gitignore

@@ -0,0 +1,4 @@
+/target/
+.settings/
+.classpath
+.project

algorithms-miscellaneous-1/README.md

@@ -0,0 +1,18 @@
+## Relevant articles:
+
+- [Validating Input With Finite Automata in Java](http://www.baeldung.com/java-finite-automata)
+- [Example of Hill Climbing Algorithm](http://www.baeldung.com/java-hill-climbing-algorithm)
+- [Monte Carlo Tree Search for Tic-Tac-Toe Game](http://www.baeldung.com/java-monte-carlo-tree-search)
+- [Binary Search Algorithm in Java](http://www.baeldung.com/java-binary-search)
+- [Introduction to Minimax Algorithm](http://www.baeldung.com/java-minimax-algorithm)
+- [How to Calculate Levenshtein Distance in Java?](http://www.baeldung.com/java-levenshtein-distance)
+- [How to Find the Kth Largest Element in Java](http://www.baeldung.com/java-kth-largest-element)
+- [Multi-Swarm Optimization Algorithm in Java](http://www.baeldung.com/java-multi-swarm-algorithm)
+- [String Search Algorithms for Large Texts](http://www.baeldung.com/java-full-text-search-algorithms)
+- [Check If a String Contains All The Letters of The Alphabet](https://www.baeldung.com/java-string-contains-all-letters)
+- [Find the Middle Element of a Linked List](http://www.baeldung.com/java-linked-list-middle-element)
+- [Calculate Factorial in Java](https://www.baeldung.com/java-calculate-factorial)
+- [Find Substrings That Are Palindromes in Java](https://www.baeldung.com/java-palindrome-substrings)
+- [Find the Longest Substring without Repeating Characters](https://www.baeldung.com/java-longest-substring-without-repeated-characters)
+- [Permutations of an Array in Java](https://www.baeldung.com/java-array-permutations)
+- [Generate Combinations in Java](https://www.baeldung.com/java-combinations-algorithm)

algorithms-miscellaneous-1/pom.xml

@@ -0,0 +1,89 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>algorithms-miscellaneous-1</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>algorithms-miscellaneous-1</name>
+    
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-math3</artifactId>
+            <version>${commons-math3.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>${guava.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>commons-codec</groupId>
+            <artifactId>commons-codec</artifactId>
+            <version>${commons-codec.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>${lombok.version}</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${org.assertj.core.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.github.dpaukov</groupId>
+            <artifactId>combinatoricslib3</artifactId>
+            <version>${combinatoricslib3.version}</version>
+         </dependency>
+    </dependencies>
+
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>org.codehaus.mojo</groupId>
+                    <artifactId>exec-maven-plugin</artifactId>
+                    <version>${exec-maven-plugin.version}</version>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+
+    <reporting>
+        <plugins>
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>cobertura-maven-plugin</artifactId>
+                <version>2.7</version>
+                <configuration>
+                    <instrumentation>
+                        <ignores>
+                            <ignore>com/baeldung/algorithms/dijkstra/*</ignore>
+                        </ignores>
+                        <excludes>
+                            <exclude>com/baeldung/algorithms/dijkstra/*</exclude>
+                        </excludes>
+                    </instrumentation>
+                </configuration>
+            </plugin>
+        </plugins>
+    </reporting>
+
+    <properties>
+        <commons-math3.version>3.6.1</commons-math3.version>
+        <org.assertj.core.version>3.9.0</org.assertj.core.version>
+        <commons-codec.version>1.11</commons-codec.version>
+        <guava.version>27.0.1-jre</guava.version>
+        <combinatoricslib3.version>3.3.0</combinatoricslib3.version>
+    </properties>
+
+</project>

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/automata/FiniteStateMachine.java

@@ -0,0 +1,20 @@
+package com.baeldung.algorithms.automata;
+
+/**
+ * Finite state machine.
+ */
+public interface FiniteStateMachine {
+
+    /**
+     * Follow a transition, switch the state of the machine.
+     * @param c Char.
+     * @return A new finite state machine with the new state.
+     */
+    FiniteStateMachine switchState(final CharSequence c);
+
+    /**
+     * Is the current state a final one?
+     * @return true or false.
+     */
+    boolean canStop();
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/automata/RtFiniteStateMachine.java

@@ -0,0 +1,30 @@
+package com.baeldung.algorithms.automata;
+
+/**
+ * Default implementation of a finite state machine.
+ * This class is immutable and thread-safe.
+ */
+public final class RtFiniteStateMachine implements FiniteStateMachine {
+
+    /**
+     * Current state.
+     */
+    private State current;
+
+    /**
+     * Ctor.
+     * @param initial Initial state of this machine.
+     */
+    public RtFiniteStateMachine(final State initial) {
+        this.current = initial;
+    }
+
+    public FiniteStateMachine switchState(final CharSequence c) {
+        return new RtFiniteStateMachine(this.current.transit(c));
+    }
+
+    public boolean canStop() {
+        return this.current.isFinal();
+    }
+
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/automata/RtState.java

@@ -0,0 +1,42 @@
+package com.baeldung.algorithms.automata;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * State in a finite state machine.
+ */
+public final class RtState implements State {
+
+    private List<Transition> transitions;
+    private boolean isFinal;
+
+    public RtState() {
+        this(false);
+    }
+    
+    public RtState(final boolean isFinal) {
+        this.transitions = new ArrayList<>();
+        this.isFinal = isFinal;
+    }
+
+    public State transit(final CharSequence c) {
+        return transitions
+          .stream()
+          .filter(t -> t.isPossible(c))
+          .map(Transition::state)
+          .findAny()
+          .orElseThrow(() -> new IllegalArgumentException("Input not accepted: " + c));
+    }
+
+    public boolean isFinal() {
+        return this.isFinal;
+    }
+
+    @Override
+    public State with(Transition tr) {
+        this.transitions.add(tr);
+        return this;
+    }
+
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/automata/RtTransition.java

@@ -0,0 +1,31 @@
+package com.baeldung.algorithms.automata;
+
+
+/**
+ * Transition in finite state machine.
+ */
+public final class RtTransition implements Transition {
+
+    private String rule;
+    private State next;
+    
+    /**
+     * Ctor.
+     * @param rule Rule that a character has to meet 
+     *  in order to get to the next state.  
+     * @param next Next state.
+     */
+    public RtTransition (String rule, State next) {
+        this.rule = rule;
+        this.next = next;
+    }
+    
+    public State state() {
+        return this.next;
+    }
+
+    public boolean isPossible(CharSequence c) {
+        return this.rule.equalsIgnoreCase(String.valueOf(c));
+    }
+
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/automata/State.java

@@ -0,0 +1,29 @@
+package com.baeldung.algorithms.automata;
+
+/**
+ * State. Part of a finite state machine.
+ */
+public interface State {
+
+    /**
+     * Add a Transition to this state.
+     * @param tr Given transition.
+     * @return Modified State.
+     */
+    State with(final Transition tr);
+
+    /**
+     * Follow one of the transitions, to get 
+     * to the next state.
+     * @param c Character.
+     * @return State.
+     * @throws IllegalStateException if the char is not accepted.
+     */
+    State transit(final CharSequence c);
+    
+    /**
+     * Can the automaton stop on this state?
+     * @return true or false
+     */
+    boolean isFinal();
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/automata/Transition.java

@@ -0,0 +1,20 @@
+package com.baeldung.algorithms.automata;
+
+/**
+ * Transition in a finite State machine.
+ */
+public interface Transition {
+
+    /**
+     * Is the transition possible with the given character?
+     * @param c char.
+     * @return true or false.
+     */
+    boolean isPossible(final CharSequence c);
+
+    /**
+     * The state to which this transition leads.
+     * @return State.
+     */
+    State state();
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/binarysearch/BinarySearch.java

@@ -0,0 +1,55 @@
+package com.baeldung.algorithms.binarysearch;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+public class BinarySearch {
+
+    public int runBinarySearchIteratively(int[] sortedArray, int key, int low, int high) {
+
+        int index = Integer.MAX_VALUE;
+
+        while (low <= high) {
+
+            int mid = (low + high) / 2;
+
+            if (sortedArray[mid] < key) {
+                low = mid + 1;
+            } else if (sortedArray[mid] > key) {
+                high = mid - 1;
+            } else if (sortedArray[mid] == key) {
+                index = mid;
+                break;
+            }
+        }
+        return index;
+    }
+
+    public int runBinarySearchRecursively(int[] sortedArray, int key, int low, int high) {
+
+        int middle = (low + high) / 2;
+        if (high < low) {
+            return -1;
+        }
+
+        if (key == sortedArray[middle]) {
+          return middle;
+        } else if (key < sortedArray[middle]) {
+          return runBinarySearchRecursively(sortedArray, key, low, middle - 1);
+        } else {
+          return runBinarySearchRecursively(sortedArray, key, middle + 1, high);
+        }
+    }
+
+    public int runBinarySearchUsingJavaArrays(int[] sortedArray, Integer key) {
+        int index = Arrays.binarySearch(sortedArray, key);
+        return index;
+    }
+
+    public int runBinarySearchUsingJavaCollections(List<Integer> sortedList, Integer key) {
+        int index = Collections.binarySearch(sortedList, key);
+        return index;
+    }
+
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/hillclimbing/HillClimbing.java

@@ -0,0 +1,189 @@
+package com.baeldung.algorithms.hillclimbing;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.Stack;
+
+public class HillClimbing {
+    public static void main(String[] args) {
+        HillClimbing hillClimbing = new HillClimbing();
+        String blockArr[] = { "B", "C", "D", "A" };
+        Stack<String> startState = hillClimbing.getStackWithValues(blockArr);
+        String goalBlockArr[] = { "A", "B", "C", "D" };
+        Stack<String> goalState = hillClimbing.getStackWithValues(goalBlockArr);
+        try {
+            List<State> solutionSequence = hillClimbing.getRouteWithHillClimbing(startState, goalState);
+            solutionSequence.forEach(HillClimbing::printEachStep);
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+    private static void printEachStep(State state) {
+        List<Stack<String>> stackList = state.getState();
+        System.out.println("----------------");
+        stackList.forEach(stack -> {
+            while (!stack.isEmpty()) {
+                System.out.println(stack.pop());
+            }
+            System.out.println(" ");
+        });
+    }
+
+    private Stack<String> getStackWithValues(String[] blocks) {
+        Stack<String> stack = new Stack<>();
+        for (String block : blocks)
+            stack.push(block);
+        return stack;
+    }
+
+    /**
+     * This method prepares path from init state to goal state
+     */
+    public List<State> getRouteWithHillClimbing(Stack<String> initStateStack, Stack<String> goalStateStack) throws Exception {
+        List<Stack<String>> initStateStackList = new ArrayList<>();
+        initStateStackList.add(initStateStack);
+        int initStateHeuristics = getHeuristicsValue(initStateStackList, goalStateStack);
+        State initState = new State(initStateStackList, initStateHeuristics);
+
+        List<State> resultPath = new ArrayList<>();
+        resultPath.add(new State(initState));
+
+        State currentState = initState;
+        boolean noStateFound = false;
+        while (!currentState.getState()
+            .get(0)
+            .equals(goalStateStack) || noStateFound) {
+            noStateFound = true;
+            State nextState = findNextState(currentState, goalStateStack);
+            if (nextState != null) {
+                noStateFound = false;
+                currentState = nextState;
+                resultPath.add(new State(nextState));
+            }
+        }
+
+        return resultPath;
+    }
+
+    /**
+     * This method finds new state from current state based on goal and
+     * heuristics
+     */
+    public State findNextState(State currentState, Stack<String> goalStateStack) {
+        List<Stack<String>> listOfStacks = currentState.getState();
+        int currentStateHeuristics = currentState.getHeuristics();
+
+        return listOfStacks.stream()
+            .map(stack -> {
+                return applyOperationsOnState(listOfStacks, stack, currentStateHeuristics, goalStateStack);
+            })
+            .filter(Objects::nonNull)
+            .findFirst()
+          .orElse(null);
+    }
+
+    /**
+     * This method applies operations on the current state to get a new state
+     */
+    public State applyOperationsOnState(List<Stack<String>> listOfStacks, Stack<String> stack, int currentStateHeuristics, Stack<String> goalStateStack) {
+        State tempState;
+        List<Stack<String>> tempStackList = new ArrayList<>(listOfStacks);
+        String block = stack.pop();
+        if (stack.size() == 0)
+            tempStackList.remove(stack);
+        tempState = pushElementToNewStack(tempStackList, block, currentStateHeuristics, goalStateStack);
+        if (tempState == null) {
+            tempState = pushElementToExistingStacks(stack, tempStackList, block, currentStateHeuristics, goalStateStack);
+        }
+        if (tempState == null)
+            stack.push(block);
+        return tempState;
+    }
+    
+    /**
+     * Operation to be applied on a state in order to find new states. This
+     * operation pushes an element into a new stack
+     */
+    private State pushElementToNewStack(List<Stack<String>> currentStackList, String block, int currentStateHeuristics, Stack<String> goalStateStack) {
+        State newState = null;
+        Stack<String> newStack = new Stack<>();
+        newStack.push(block);
+
+        currentStackList.add(newStack);
+        int newStateHeuristics = getHeuristicsValue(currentStackList, goalStateStack);
+        if (newStateHeuristics > currentStateHeuristics) {
+            newState = new State(currentStackList, newStateHeuristics);
+        } else {
+            currentStackList.remove(newStack);
+        }
+        return newState;
+    }
+
+    /**
+     * Operation to be applied on a state in order to find new states. This
+     * operation pushes an element into one of the other stacks to explore new
+     * states
+     */
+    private State pushElementToExistingStacks(Stack currentStack, List<Stack<String>> currentStackList, String block, int currentStateHeuristics, Stack<String> goalStateStack) {
+
+        Optional<State> newState = currentStackList.stream()
+            .filter(stack -> stack != currentStack)
+            .map(stack -> {
+                return pushElementToStack(stack, block, currentStackList, currentStateHeuristics, goalStateStack);
+            })
+            .filter(Objects::nonNull)
+            .findFirst();
+
+        return newState.orElse(null);
+    }
+    
+    /**
+     * This method pushes a block to the stack and returns new state if its closer to goal
+     */
+    private State pushElementToStack(Stack stack, String block, List<Stack<String>> currentStackList, int currentStateHeuristics, Stack<String> goalStateStack) {
+        stack.push(block);
+        int newStateHeuristics = getHeuristicsValue(currentStackList, goalStateStack);
+        if (newStateHeuristics > currentStateHeuristics) {
+            return new State(currentStackList, newStateHeuristics);
+        }
+        stack.pop();
+        return null;
+    }
+
+    /**
+     * This method returns heuristics value for given state with respect to goal
+     * state
+     */
+    public int getHeuristicsValue(List<Stack<String>> currentState, Stack<String> goalStateStack) {
+        Integer heuristicValue;
+        heuristicValue = currentState.stream()
+            .mapToInt(stack -> {
+                return getHeuristicsValueForStack(stack, currentState, goalStateStack);
+            })
+            .sum();
+        return heuristicValue;
+    }
+    
+    /**
+     * This method returns heuristics value for a particular stack
+     */
+    public int getHeuristicsValueForStack(Stack<String> stack, List<Stack<String>> currentState, Stack<String> goalStateStack) {
+        int stackHeuristics = 0;
+        boolean isPositioneCorrect = true;
+        int goalStartIndex = 0;
+        for (String currentBlock : stack) {
+            if (isPositioneCorrect && currentBlock.equals(goalStateStack.get(goalStartIndex))) {
+                stackHeuristics += goalStartIndex;
+            } else {
+                stackHeuristics -= goalStartIndex;
+                isPositioneCorrect = false;
+            }
+            goalStartIndex++;
+        }
+        return stackHeuristics;
+    }
+
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/hillclimbing/State.java

@@ -0,0 +1,43 @@
+package com.baeldung.algorithms.hillclimbing;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Stack;
+
+public class State {
+    private List<Stack<String>> state;
+    private int heuristics;
+
+    public State(List<Stack<String>> state) {
+        this.state = state;
+    }
+
+    State(List<Stack<String>> state, int heuristics) {
+        this.state = state;
+        this.heuristics = heuristics;
+    }
+
+    State(State state) {
+        if (state != null) {
+            this.state = new ArrayList<>();
+            for (Stack s : state.getState()) {
+                Stack s1;
+                s1 = (Stack) s.clone();
+                this.state.add(s1);
+            }
+            this.heuristics = state.getHeuristics();
+        }
+    }
+
+    public List<Stack<String>> getState() {
+        return state;
+    }
+
+    public int getHeuristics() {
+        return heuristics;
+    }
+
+    public void setHeuristics(int heuristics) {
+        this.heuristics = heuristics;
+    }
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/kthlargest/FindKthLargest.java

@@ -0,0 +1,111 @@
+package com.baeldung.algorithms.kthlargest;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.stream.IntStream;
+
+public class FindKthLargest {
+
+    public int findKthLargestBySorting(Integer[] arr, int k) {
+        Arrays.sort(arr);
+        int targetIndex = arr.length - k;
+        return arr[targetIndex];
+    }
+
+    public int findKthLargestBySortingDesc(Integer[] arr, int k) {
+        Arrays.sort(arr, Collections.reverseOrder());
+        return arr[k - 1];
+    }
+
+    public int findKthElementByQuickSelect(Integer[] arr, int left, int right, int k) {
+        if (k >= 0 && k <= right - left + 1) {
+            int pos = partition(arr, left, right);
+            if (pos - left == k) {
+                return arr[pos];
+            }
+            if (pos - left > k) {
+                return findKthElementByQuickSelect(arr, left, pos - 1, k);
+            }
+            return findKthElementByQuickSelect(arr, pos + 1, right, k - pos + left - 1);
+        }
+        return 0;
+    }
+
+    public int findKthElementByQuickSelectWithIterativePartition(Integer[] arr, int left, int right, int k) {
+        if (k >= 0 && k <= right - left + 1) {
+            int pos = partitionIterative(arr, left, right);
+            if (pos - left == k) {
+                return arr[pos];
+            }
+            if (pos - left > k) {
+                return findKthElementByQuickSelectWithIterativePartition(arr, left, pos - 1, k);
+            }
+            return findKthElementByQuickSelectWithIterativePartition(arr, pos + 1, right, k - pos + left - 1);
+        }
+        return 0;
+    }
+
+    private int partition(Integer[] arr, int left, int right) {
+        int pivot = arr[right];
+        Integer[] leftArr;
+        Integer[] rightArr;
+
+        leftArr = IntStream.range(left, right)
+            .filter(i -> arr[i] < pivot)
+            .map(i -> arr[i])
+            .boxed()
+            .toArray(Integer[]::new);
+
+        rightArr = IntStream.range(left, right)
+            .filter(i -> arr[i] > pivot)
+            .map(i -> arr[i])
+            .boxed()
+            .toArray(Integer[]::new);
+
+        int leftArraySize = leftArr.length;
+        System.arraycopy(leftArr, 0, arr, left, leftArraySize);
+        arr[leftArraySize + left] = pivot;
+        System.arraycopy(rightArr, 0, arr, left + leftArraySize + 1, rightArr.length);
+
+        return left + leftArraySize;
+    }
+
+    private int partitionIterative(Integer[] arr, int left, int right) {
+        int pivot = arr[right], i = left;
+        for (int j = left; j <= right - 1; j++) {
+            if (arr[j] <= pivot) {
+                swap(arr, i, j);
+                i++;
+            }
+        }
+        swap(arr, i, right);
+        return i;
+    }
+
+    public int findKthElementByRandomizedQuickSelect(Integer[] arr, int left, int right, int k) {
+        if (k >= 0 && k <= right - left + 1) {
+            int pos = randomPartition(arr, left, right);
+            if (pos - left == k) {
+                return arr[pos];
+            }
+            if (pos - left > k) {
+                return findKthElementByRandomizedQuickSelect(arr, left, pos - 1, k);
+            }
+            return findKthElementByRandomizedQuickSelect(arr, pos + 1, right, k - pos + left - 1);
+        }
+        return 0;
+    }
+
+    private int randomPartition(Integer arr[], int left, int right) {
+        int n = right - left + 1;
+        int pivot = (int) (Math.random() * n);
+        swap(arr, left + pivot, right);
+        return partition(arr, left, right);
+    }
+
+    private void swap(Integer[] arr, int n1, int n2) {
+        int temp = arr[n2];
+        arr[n2] = arr[n1];
+        arr[n1] = temp;
+    }
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/mcts/montecarlo/MonteCarloTreeSearch.java

@@ -0,0 +1,109 @@
+package com.baeldung.algorithms.mcts.montecarlo;
+
+import java.util.List;
+
+import com.baeldung.algorithms.mcts.tictactoe.Board;
+import com.baeldung.algorithms.mcts.tree.Node;
+import com.baeldung.algorithms.mcts.tree.Tree;
+
+public class MonteCarloTreeSearch {
+
+    private static final int WIN_SCORE = 10;
+    private int level;
+    private int opponent;
+
+    public MonteCarloTreeSearch() {
+        this.level = 3;
+    }
+
+    public int getLevel() {
+        return level;
+    }
+
+    public void setLevel(int level) {
+        this.level = level;
+    }
+
+    private int getMillisForCurrentLevel() {
+        return 2 * (this.level - 1) + 1;
+    }
+
+    public Board findNextMove(Board board, int playerNo) {
+        long start = System.currentTimeMillis();
+        long end = start + 60 * getMillisForCurrentLevel();
+
+        opponent = 3 - playerNo;
+        Tree tree = new Tree();
+        Node rootNode = tree.getRoot();
+        rootNode.getState().setBoard(board);
+        rootNode.getState().setPlayerNo(opponent);
+
+        while (System.currentTimeMillis() < end) {
+            // Phase 1 - Selection
+            Node promisingNode = selectPromisingNode(rootNode);
+            // Phase 2 - Expansion
+            if (promisingNode.getState().getBoard().checkStatus() == Board.IN_PROGRESS)
+                expandNode(promisingNode);
+
+            // Phase 3 - Simulation
+            Node nodeToExplore = promisingNode;
+            if (promisingNode.getChildArray().size() > 0) {
+                nodeToExplore = promisingNode.getRandomChildNode();
+            }
+            int playoutResult = simulateRandomPlayout(nodeToExplore);
+            // Phase 4 - Update
+            backPropogation(nodeToExplore, playoutResult);
+        }
+
+        Node winnerNode = rootNode.getChildWithMaxScore();
+        tree.setRoot(winnerNode);
+        return winnerNode.getState().getBoard();
+    }
+
+    private Node selectPromisingNode(Node rootNode) {
+        Node node = rootNode;
+        while (node.getChildArray().size() != 0) {
+            node = UCT.findBestNodeWithUCT(node);
+        }
+        return node;
+    }
+
+    private void expandNode(Node node) {
+        List<State> possibleStates = node.getState().getAllPossibleStates();
+        possibleStates.forEach(state -> {
+            Node newNode = new Node(state);
+            newNode.setParent(node);
+            newNode.getState().setPlayerNo(node.getState().getOpponent());
+            node.getChildArray().add(newNode);
+        });
+    }
+
+    private void backPropogation(Node nodeToExplore, int playerNo) {
+        Node tempNode = nodeToExplore;
+        while (tempNode != null) {
+            tempNode.getState().incrementVisit();
+            if (tempNode.getState().getPlayerNo() == playerNo)
+                tempNode.getState().addScore(WIN_SCORE);
+            tempNode = tempNode.getParent();
+        }
+    }
+
+    private int simulateRandomPlayout(Node node) {
+        Node tempNode = new Node(node);
+        State tempState = tempNode.getState();
+        int boardStatus = tempState.getBoard().checkStatus();
+
+        if (boardStatus == opponent) {
+            tempNode.getParent().getState().setWinScore(Integer.MIN_VALUE);
+            return boardStatus;
+        }
+        while (boardStatus == Board.IN_PROGRESS) {
+            tempState.togglePlayer();
+            tempState.randomPlay();
+            boardStatus = tempState.getBoard().checkStatus();
+        }
+
+        return boardStatus;
+    }
+
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/mcts/montecarlo/State.java

@@ -0,0 +1,97 @@
+package com.baeldung.algorithms.mcts.montecarlo;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import com.baeldung.algorithms.mcts.tictactoe.Board;
+import com.baeldung.algorithms.mcts.tictactoe.Position;
+
+public class State {
+    private Board board;
+    private int playerNo;
+    private int visitCount;
+    private double winScore;
+
+    public State() {
+        board = new Board();
+    }
+
+    public State(State state) {
+        this.board = new Board(state.getBoard());
+        this.playerNo = state.getPlayerNo();
+        this.visitCount = state.getVisitCount();
+        this.winScore = state.getWinScore();
+    }
+
+    public State(Board board) {
+        this.board = new Board(board);
+    }
+
+    Board getBoard() {
+        return board;
+    }
+
+    void setBoard(Board board) {
+        this.board = board;
+    }
+
+    int getPlayerNo() {
+        return playerNo;
+    }
+
+    void setPlayerNo(int playerNo) {
+        this.playerNo = playerNo;
+    }
+
+    int getOpponent() {
+        return 3 - playerNo;
+    }
+
+    public int getVisitCount() {
+        return visitCount;
+    }
+
+    public void setVisitCount(int visitCount) {
+        this.visitCount = visitCount;
+    }
+
+    double getWinScore() {
+        return winScore;
+    }
+
+    void setWinScore(double winScore) {
+        this.winScore = winScore;
+    }
+
+    public List<State> getAllPossibleStates() {
+        List<State> possibleStates = new ArrayList<>();
+        List<Position> availablePositions = this.board.getEmptyPositions();
+        availablePositions.forEach(p -> {
+            State newState = new State(this.board);
+            newState.setPlayerNo(3 - this.playerNo);
+            newState.getBoard().performMove(newState.getPlayerNo(), p);
+            possibleStates.add(newState);
+        });
+        return possibleStates;
+    }
+
+    void incrementVisit() {
+        this.visitCount++;
+    }
+
+    void addScore(double score) {
+        if (this.winScore != Integer.MIN_VALUE)
+            this.winScore += score;
+    }
+
+    void randomPlay() {
+        List<Position> availablePositions = this.board.getEmptyPositions();
+        int totalPossibilities = availablePositions.size();
+        int selectRandom = (int) (Math.random() * totalPossibilities);
+        this.board.performMove(this.playerNo, availablePositions.get(selectRandom));
+    }
+
+    void togglePlayer() {
+        this.playerNo = 3 - this.playerNo;
+    }
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/mcts/montecarlo/UCT.java

@@ -0,0 +1,24 @@
+package com.baeldung.algorithms.mcts.montecarlo;
+
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+import com.baeldung.algorithms.mcts.tree.Node;
+
+public class UCT {
+
+    public static double uctValue(int totalVisit, double nodeWinScore, int nodeVisit) {
+        if (nodeVisit == 0) {
+            return Integer.MAX_VALUE;
+        }
+        return (nodeWinScore / (double) nodeVisit) + 1.41 * Math.sqrt(Math.log(totalVisit) / (double) nodeVisit);
+    }
+
+    static Node findBestNodeWithUCT(Node node) {
+        int parentVisit = node.getState().getVisitCount();
+        return Collections.max(
+          node.getChildArray(),
+          Comparator.comparing(c -> uctValue(parentVisit, c.getState().getWinScore(), c.getState().getVisitCount())));
+    }
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/mcts/tictactoe/Board.java

@@ -0,0 +1,155 @@
+package com.baeldung.algorithms.mcts.tictactoe;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class Board {
+    int[][] boardValues;
+    int totalMoves;
+
+    public static final int DEFAULT_BOARD_SIZE = 3;
+
+    public static final int IN_PROGRESS = -1;
+    public static final int DRAW = 0;
+    public static final int P1 = 1;
+    public static final int P2 = 2;
+
+    public Board() {
+        boardValues = new int[DEFAULT_BOARD_SIZE][DEFAULT_BOARD_SIZE];
+    }
+
+    public Board(int boardSize) {
+        boardValues = new int[boardSize][boardSize];
+    }
+
+    public Board(int[][] boardValues) {
+        this.boardValues = boardValues;
+    }
+
+    public Board(int[][] boardValues, int totalMoves) {
+        this.boardValues = boardValues;
+        this.totalMoves = totalMoves;
+    }
+
+    public Board(Board board) {
+        int boardLength = board.getBoardValues().length;
+        this.boardValues = new int[boardLength][boardLength];
+        int[][] boardValues = board.getBoardValues();
+        int n = boardValues.length;
+        for (int i = 0; i < n; i++) {
+            int m = boardValues[i].length;
+            for (int j = 0; j < m; j++) {
+                this.boardValues[i][j] = boardValues[i][j];
+            }
+        }
+    }
+
+    public void performMove(int player, Position p) {
+        this.totalMoves++;
+        boardValues[p.getX()][p.getY()] = player;
+    }
+
+    public int[][] getBoardValues() {
+        return boardValues;
+    }
+
+    public void setBoardValues(int[][] boardValues) {
+        this.boardValues = boardValues;
+    }
+
+    public int checkStatus() {
+        int boardSize = boardValues.length;
+        int maxIndex = boardSize - 1;
+        int[] diag1 = new int[boardSize];
+        int[] diag2 = new int[boardSize];
+        
+        for (int i = 0; i < boardSize; i++) {
+            int[] row = boardValues[i];
+            int[] col = new int[boardSize];
+            for (int j = 0; j < boardSize; j++) {
+                col[j] = boardValues[j][i];
+            }
+            
+            int checkRowForWin = checkForWin(row);
+            if(checkRowForWin!=0)
+                return checkRowForWin;
+            
+            int checkColForWin = checkForWin(col);
+            if(checkColForWin!=0)
+                return checkColForWin;
+            
+            diag1[i] = boardValues[i][i];
+            diag2[i] = boardValues[maxIndex - i][i];
+        }
+
+        int checkDia1gForWin = checkForWin(diag1);
+        if(checkDia1gForWin!=0)
+            return checkDia1gForWin;
+        
+        int checkDiag2ForWin = checkForWin(diag2);
+        if(checkDiag2ForWin!=0)
+            return checkDiag2ForWin;
+        
+        if (getEmptyPositions().size() > 0)
+            return IN_PROGRESS;
+        else
+            return DRAW;
+    }
+
+    private int checkForWin(int[] row) {
+        boolean isEqual = true;
+        int size = row.length;
+        int previous = row[0];
+        for (int i = 0; i < size; i++) {
+            if (previous != row[i]) {
+                isEqual = false;
+                break;
+            }
+            previous = row[i];
+        }
+        if(isEqual)
+            return previous;
+        else
+            return 0;
+    }
+
+    public void printBoard() {
+        int size = this.boardValues.length;
+        for (int i = 0; i < size; i++) {
+            for (int j = 0; j < size; j++) {
+                System.out.print(boardValues[i][j] + " ");
+            }
+            System.out.println();
+        }
+    }
+
+    public List<Position> getEmptyPositions() {
+        int size = this.boardValues.length;
+        List<Position> emptyPositions = new ArrayList<>();
+        for (int i = 0; i < size; i++) {
+            for (int j = 0; j < size; j++) {
+                if (boardValues[i][j] == 0)
+                    emptyPositions.add(new Position(i, j));
+            }
+        }
+        return emptyPositions;
+    }
+
+    public void printStatus() {
+        switch (this.checkStatus()) {
+        case P1:
+            System.out.println("Player 1 wins");
+            break;
+        case P2:
+            System.out.println("Player 2 wins");
+            break;
+        case DRAW:
+            System.out.println("Game Draw");
+            break;
+        case IN_PROGRESS:
+            System.out.println("Game In Progress");
+            break;
+        }
+    }
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/mcts/tictactoe/Position.java

@@ -0,0 +1,31 @@
+package com.baeldung.algorithms.mcts.tictactoe;
+
+public class Position {
+    int x;
+    int y;
+
+    public Position() {
+    }
+
+    public Position(int x, int y) {
+        this.x = x;
+        this.y = y;
+    }
+
+    public int getX() {
+        return x;
+    }
+
+    public void setX(int x) {
+        this.x = x;
+    }
+
+    public int getY() {
+        return y;
+    }
+
+    public void setY(int y) {
+        this.y = y;
+    }
+
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/mcts/tree/Node.java

@@ -0,0 +1,78 @@
+package com.baeldung.algorithms.mcts.tree;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+import com.baeldung.algorithms.mcts.montecarlo.State;
+
+public class Node {
+    State state;
+    Node parent;
+    List<Node> childArray;
+
+    public Node() {
+        this.state = new State();
+        childArray = new ArrayList<>();
+    }
+
+    public Node(State state) {
+        this.state = state;
+        childArray = new ArrayList<>();
+    }
+
+    public Node(State state, Node parent, List<Node> childArray) {
+        this.state = state;
+        this.parent = parent;
+        this.childArray = childArray;
+    }
+
+    public Node(Node node) {
+        this.childArray = new ArrayList<>();
+        this.state = new State(node.getState());
+        if (node.getParent() != null)
+            this.parent = node.getParent();
+        List<Node> childArray = node.getChildArray();
+        for (Node child : childArray) {
+            this.childArray.add(new Node(child));
+        }
+    }
+
+    public State getState() {
+        return state;
+    }
+
+    public void setState(State state) {
+        this.state = state;
+    }
+
+    public Node getParent() {
+        return parent;
+    }
+
+    public void setParent(Node parent) {
+        this.parent = parent;
+    }
+
+    public List<Node> getChildArray() {
+        return childArray;
+    }
+
+    public void setChildArray(List<Node> childArray) {
+        this.childArray = childArray;
+    }
+
+    public Node getRandomChildNode() {
+        int noOfPossibleMoves = this.childArray.size();
+        int selectRandom = (int) (Math.random() * noOfPossibleMoves);
+        return this.childArray.get(selectRandom);
+    }
+
+    public Node getChildWithMaxScore() {
+        return Collections.max(this.childArray, Comparator.comparing(c -> {
+            return c.getState().getVisitCount();
+        }));
+    }
+
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/mcts/tree/Tree.java

@@ -0,0 +1,26 @@
+package com.baeldung.algorithms.mcts.tree;
+
+public class Tree {
+    Node root;
+
+    public Tree() {
+        root = new Node();
+    }
+
+    public Tree(Node root) {
+        this.root = root;
+    }
+
+    public Node getRoot() {
+        return root;
+    }
+
+    public void setRoot(Node root) {
+        this.root = root;
+    }
+
+    public void addChild(Node parent, Node child) {
+        parent.getChildArray().add(child);
+    }
+
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/middleelementlookup/MiddleElementLookup.java

@@ -0,0 +1,88 @@
+package com.baeldung.algorithms.middleelementlookup;
+
+import java.util.LinkedList;
+import java.util.Optional;
+
+public class MiddleElementLookup {
+
+    public static Optional<String> findMiddleElementLinkedList(LinkedList<String> linkedList) {
+        if (linkedList == null || linkedList.isEmpty()) {
+            return Optional.empty();
+        }
+
+        return Optional.ofNullable(linkedList.get((linkedList.size() - 1) / 2));
+    }
+
+    public static Optional<String> findMiddleElementFromHead(Node head) {
+        if (head == null) {
+            return Optional.empty();
+        }
+
+        // calculate the size of the list
+        Node current = head;
+        int size = 1;
+        while (current.hasNext()) {
+            current = current.next();
+            size++;
+        }
+
+        // iterate till the middle element
+        current = head;
+        for (int i = 0; i < (size - 1) / 2; i++) {
+            current = current.next();
+        }
+
+        return Optional.ofNullable(current.data());
+    }
+
+    public static Optional<String> findMiddleElementFromHead1PassRecursively(Node head) {
+        if (head == null) {
+            return Optional.empty();
+        }
+
+        MiddleAuxRecursion middleAux = new MiddleAuxRecursion();
+        findMiddleRecursively(head, middleAux);
+        return Optional.ofNullable(middleAux.middle.data());
+    }
+
+    private static void findMiddleRecursively(Node node, MiddleAuxRecursion middleAux) {
+        if (node == null) {
+            // reached the end
+            middleAux.length = middleAux.length / 2;
+            return;
+        }
+        middleAux.length++;
+        findMiddleRecursively(node.next(), middleAux);
+
+        if (middleAux.length == 0) {
+            // found the middle
+            middleAux.middle = node;
+        }
+
+        middleAux.length--;
+    }
+
+    public static Optional<String> findMiddleElementFromHead1PassIteratively(Node head) {
+        if (head == null) {
+            return Optional.empty();
+        }
+
+        Node slowPointer = head;
+        Node fastPointer = head;
+
+        while (fastPointer.hasNext() && fastPointer.next()
+            .hasNext()) {
+            fastPointer = fastPointer.next()
+                .next();
+            slowPointer = slowPointer.next();
+        }
+
+        return Optional.ofNullable(slowPointer.data());
+    }
+
+    private static class MiddleAuxRecursion {
+        Node middle;
+        int length = 0;
+    }
+
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/middleelementlookup/Node.java

@@ -0,0 +1,34 @@
+package com.baeldung.algorithms.middleelementlookup;
+
+public class Node {
+    private Node next;
+    private String data;
+
+    public Node(String data) {
+        this.data = data;
+    }
+
+    public String data() {
+        return data;
+    }
+
+    public void setData(String data) {
+        this.data = data;
+    }
+
+    public boolean hasNext() {
+        return next != null;
+    }
+
+    public Node next() {
+        return next;
+    }
+
+    public void setNext(Node next) {
+        this.next = next;
+    }
+
+    public String toString() {
+        return this.data;
+    }
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/minimax/GameOfBones.java

@@ -0,0 +1,14 @@
+package com.baeldung.algorithms.minimax;
+
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+
+class GameOfBones {
+    static List<Integer> getPossibleStates(int noOfBonesInHeap) {
+        return IntStream.rangeClosed(1, 3).boxed()
+          .map(i -> noOfBonesInHeap - i)
+          .filter(newHeapCount -> newHeapCount >= 0)
+          .collect(Collectors.toList());
+    }
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/minimax/MiniMax.java

@@ -0,0 +1,60 @@
+package com.baeldung.algorithms.minimax;
+
+import java.util.Comparator;
+import java.util.List;
+import java.util.NoSuchElementException;
+
+public class MiniMax {
+    private Tree tree;
+
+    public Tree getTree() {
+        return tree;
+    }
+
+    public void constructTree(int noOfBones) {
+        tree = new Tree();
+        Node root = new Node(noOfBones, true);
+        tree.setRoot(root);
+        constructTree(root);
+    }
+
+    private void constructTree(Node parentNode) {
+        List<Integer> listofPossibleHeaps = GameOfBones.getPossibleStates(parentNode.getNoOfBones());
+        boolean isChildMaxPlayer = !parentNode.isMaxPlayer();
+        listofPossibleHeaps.forEach(n -> {
+            Node newNode = new Node(n, isChildMaxPlayer);
+            parentNode.addChild(newNode);
+            if (newNode.getNoOfBones() > 0) {
+                constructTree(newNode);
+            }
+        });
+    }
+
+    public boolean checkWin() {
+        Node root = tree.getRoot();
+        checkWin(root);
+        return root.getScore() == 1;
+    }
+
+    private void checkWin(Node node) {
+        List<Node> children = node.getChildren();
+        boolean isMaxPlayer = node.isMaxPlayer();
+        children.forEach(child -> {
+            if (child.getNoOfBones() == 0) {
+                child.setScore(isMaxPlayer ? 1 : -1);
+            } else {
+                checkWin(child);
+            }
+        });
+        Node bestChild = findBestChild(isMaxPlayer, children);
+        node.setScore(bestChild.getScore());
+    }
+
+    private Node findBestChild(boolean isMaxPlayer, List<Node> children) {
+        Comparator<Node> byScoreComparator = Comparator.comparing(Node::getScore);
+
+        return children.stream()
+          .max(isMaxPlayer ? byScoreComparator : byScoreComparator.reversed())
+          .orElseThrow(NoSuchElementException::new);
+    }
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/minimax/Node.java

@@ -0,0 +1,42 @@
+package com.baeldung.algorithms.minimax;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Node {
+    private int noOfBones;
+    private boolean isMaxPlayer;
+    private int score;
+    private List<Node> children;
+
+    public Node(int noOfBones, boolean isMaxPlayer) {
+        this.noOfBones = noOfBones;
+        this.isMaxPlayer = isMaxPlayer;
+        children = new ArrayList<>();
+    }
+
+    int getNoOfBones() {
+        return noOfBones;
+    }
+
+    boolean isMaxPlayer() {
+        return isMaxPlayer;
+    }
+
+    int getScore() {
+        return score;
+    }
+
+    void setScore(int score) {
+        this.score = score;
+    }
+
+    List<Node> getChildren() {
+        return children;
+    }
+
+    void addChild(Node newNode) {
+        children.add(newNode);
+    }
+
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/minimax/Tree.java

@@ -0,0 +1,16 @@
+package com.baeldung.algorithms.minimax;
+
+public class Tree {
+    private Node root;
+
+    Tree() {
+    }
+
+    Node getRoot() {
+        return root;
+    }
+
+    void setRoot(Node root) {
+        this.root = root;
+    }
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/multiswarm/Constants.java

@@ -0,0 +1,47 @@
+package com.baeldung.algorithms.multiswarm;
+
+/**
+ * Constants used by the Multi-swarm optimization algorithms.
+ * 
+ * @author Donato Rimenti
+ *
+ */
+public class Constants {
+
+	/**
+	 * The inertia factor encourages a particle to continue moving in its
+	 * current direction.
+	 */
+	public static final double INERTIA_FACTOR = 0.729;
+
+	/**
+	 * The cognitive weight encourages a particle to move toward its historical
+	 * best-known position.
+	 */
+	public static final double COGNITIVE_WEIGHT = 1.49445;
+
+	/**
+	 * The social weight encourages a particle to move toward the best-known
+	 * position found by any of the particle’s swarm-mates.
+	 */
+	public static final double SOCIAL_WEIGHT = 1.49445;
+
+	/**
+	 * The global weight encourages a particle to move toward the best-known
+	 * position found by any particle in any swarm.
+	 */
+	public static final double GLOBAL_WEIGHT = 0.3645;
+
+	/**
+	 * Upper bound for the random generation. We use it to reduce the
+	 * computation time since we can rawly estimate it.
+	 */
+	public static final int PARTICLE_UPPER_BOUND = 10000000;
+
+	/**
+	 * Private constructor for utility class.
+	 */
+	private Constants() {
+	}
+
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/multiswarm/FitnessFunction.java

@@ -0,0 +1,21 @@
+package com.baeldung.algorithms.multiswarm;
+
+/**
+ * Interface for a fitness function, used to decouple the main algorithm logic
+ * from the specific problem solution.
+ * 
+ * @author Donato Rimenti
+ *
+ */
+public interface FitnessFunction {
+
+	/**
+	 * Returns the fitness of a particle given its position.
+	 * 
+	 * @param particlePosition
+	 *            the position of the particle
+	 * @return the fitness of the particle
+	 */
+	public double getFitness(long[] particlePosition);
+
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/multiswarm/Multiswarm.java

@@ -0,0 +1,227 @@
+package com.baeldung.algorithms.multiswarm;
+
+import java.util.Arrays;
+import java.util.Random;
+
+/**
+ * Represents a collection of {@link Swarm}.
+ * 
+ * @author Donato Rimenti
+ *
+ */
+public class Multiswarm {
+
+	/**
+	 * The swarms managed by this multiswarm.
+	 */
+	private Swarm[] swarms;
+
+	/**
+	 * The best position found within all the {@link #swarms}.
+	 */
+	private long[] bestPosition;
+
+	/**
+	 * The best fitness score found within all the {@link #swarms}.
+	 */
+	private double bestFitness = Double.NEGATIVE_INFINITY;
+
+	/**
+	 * A random generator.
+	 */
+	private Random random = new Random();
+
+	/**
+	 * The fitness function used to determine how good is a particle.
+	 */
+	private FitnessFunction fitnessFunction;
+
+	/**
+	 * Instantiates a new Multiswarm.
+	 * 
+	 * @param numSwarms
+	 *            the number of {@link #swarms}
+	 * @param particlesPerSwarm
+	 *            the number of particle for each {@link #swarms}
+	 * @param fitnessFunction
+	 *            the {@link #fitnessFunction}
+	 */
+	public Multiswarm(int numSwarms, int particlesPerSwarm, FitnessFunction fitnessFunction) {
+		this.fitnessFunction = fitnessFunction;
+		this.swarms = new Swarm[numSwarms];
+		for (int i = 0; i < numSwarms; i++) {
+			swarms[i] = new Swarm(particlesPerSwarm);
+		}
+	}
+
+	/**
+	 * Main loop of the algorithm. Iterates all particles of all
+	 * {@link #swarms}. For each particle, computes the new fitness and checks
+	 * if a new best position has been found among itself, the swarm and all the
+	 * swarms and finally updates the particle position and speed.
+	 */
+	public void mainLoop() {
+		for (Swarm swarm : swarms) {
+			for (Particle particle : swarm.getParticles()) {
+
+				long[] particleOldPosition = particle.getPosition().clone();
+
+				// Calculate the particle fitness.
+				particle.setFitness(fitnessFunction.getFitness(particleOldPosition));
+
+				// Check if a new best position has been found for the particle
+				// itself, within the swarm and the multiswarm.
+				if (particle.getFitness() > particle.getBestFitness()) {
+					particle.setBestFitness(particle.getFitness());
+					particle.setBestPosition(particleOldPosition);
+
+					if (particle.getFitness() > swarm.getBestFitness()) {
+						swarm.setBestFitness(particle.getFitness());
+						swarm.setBestPosition(particleOldPosition);
+
+						if (swarm.getBestFitness() > bestFitness) {
+							bestFitness = swarm.getBestFitness();
+							bestPosition = swarm.getBestPosition().clone();
+						}
+
+					}
+				}
+
+				// Updates the particle position by adding the speed to the
+				// actual position.
+				long[] position = particle.getPosition();
+				long[] speed = particle.getSpeed();
+
+				position[0] += speed[0];
+				position[1] += speed[1];
+
+				// Updates the particle speed.
+				speed[0] = getNewParticleSpeedForIndex(particle, swarm, 0);
+				speed[1] = getNewParticleSpeedForIndex(particle, swarm, 1);
+			}
+		}
+	}
+
+	/**
+	 * Computes a new speed for a given particle of a given swarm on a given
+	 * axis. The new speed is computed using the formula:
+	 * 
+	 * <pre>
+	 * ({@link Constants#INERTIA_FACTOR} * {@link Particle#getSpeed()}) + 
+	 * (({@link Constants#COGNITIVE_WEIGHT} * random(0,1)) * ({@link Particle#getBestPosition()} - {@link Particle#getPosition()})) +
+	 * (({@link Constants#SOCIAL_WEIGHT} * random(0,1)) * ({@link Swarm#getBestPosition()} - {@link Particle#getPosition()})) + 
+	 * (({@link Constants#GLOBAL_WEIGHT} * random(0,1)) * ({@link #bestPosition} - {@link Particle#getPosition()}))
+	 * </pre>
+	 *
+	 * @param particle
+	 *            the particle whose new speed needs to be computed
+	 * @param swarm
+	 *            the swarm which contains the particle
+	 * @param index
+	 *            the index of the particle axis whose speeds needs to be
+	 *            computed
+	 * @return the new speed of the particle passed on the given axis
+	 */
+	private int getNewParticleSpeedForIndex(Particle particle, Swarm swarm, int index) {
+		return (int) ((Constants.INERTIA_FACTOR * particle.getSpeed()[index])
+				+ (randomizePercentage(Constants.COGNITIVE_WEIGHT)
+						* (particle.getBestPosition()[index] - particle.getPosition()[index]))
+				+ (randomizePercentage(Constants.SOCIAL_WEIGHT)
+						* (swarm.getBestPosition()[index] - particle.getPosition()[index]))
+				+ (randomizePercentage(Constants.GLOBAL_WEIGHT)
+						* (bestPosition[index] - particle.getPosition()[index])));
+	}
+
+	/**
+	 * Returns a random number between 0 and the value passed as argument.
+	 *
+	 * @param value
+	 *            the value to randomize
+	 * @return a random value between 0 and the one passed as argument
+	 */
+	private double randomizePercentage(double value) {
+		return random.nextDouble() * value;
+	}
+
+	/**
+	 * Gets the {@link #bestPosition}.
+	 *
+	 * @return the {@link #bestPosition}
+	 */
+	public long[] getBestPosition() {
+		return bestPosition;
+	}
+
+	/**
+	 * Gets the {@link #bestFitness}.
+	 *
+	 * @return the {@link #bestFitness}
+	 */
+	public double getBestFitness() {
+		return bestFitness;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see java.lang.Object#hashCode()
+	 */
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		long temp;
+		temp = Double.doubleToLongBits(bestFitness);
+		result = prime * result + (int) (temp ^ (temp >>> 32));
+		result = prime * result + Arrays.hashCode(bestPosition);
+		result = prime * result + ((fitnessFunction == null) ? 0 : fitnessFunction.hashCode());
+		result = prime * result + ((random == null) ? 0 : random.hashCode());
+		result = prime * result + Arrays.hashCode(swarms);
+		return result;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see java.lang.Object#equals(java.lang.Object)
+	 */
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null)
+			return false;
+		if (getClass() != obj.getClass())
+			return false;
+		Multiswarm other = (Multiswarm) obj;
+		if (Double.doubleToLongBits(bestFitness) != Double.doubleToLongBits(other.bestFitness))
+			return false;
+		if (!Arrays.equals(bestPosition, other.bestPosition))
+			return false;
+		if (fitnessFunction == null) {
+			if (other.fitnessFunction != null)
+				return false;
+		} else if (!fitnessFunction.equals(other.fitnessFunction))
+			return false;
+		if (random == null) {
+			if (other.random != null)
+				return false;
+		} else if (!random.equals(other.random))
+			return false;
+		if (!Arrays.equals(swarms, other.swarms))
+			return false;
+		return true;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see java.lang.Object#toString()
+	 */
+	@Override
+	public String toString() {
+		return "Multiswarm [swarms=" + Arrays.toString(swarms) + ", bestPosition=" + Arrays.toString(bestPosition)
+				+ ", bestFitness=" + bestFitness + ", random=" + random + ", fitnessFunction=" + fitnessFunction + "]";
+	}
+
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/multiswarm/Particle.java

@@ -0,0 +1,204 @@
+package com.baeldung.algorithms.multiswarm;
+
+import java.util.Arrays;
+
+/**
+ * Represents a particle, the basic component of a {@link Swarm}.
+ * 
+ * @author Donato Rimenti
+ * 
+ */
+public class Particle {
+
+	/**
+	 * The current position of this particle.
+	 */
+	private long[] position;
+
+	/**
+	 * The speed of this particle.
+	 */
+	private long[] speed;
+
+	/**
+	 * The fitness of this particle for the current position.
+	 */
+	private double fitness;
+
+	/**
+	 * The best position found by this particle.
+	 */
+	private long[] bestPosition;
+
+	/**
+	 * The best fitness found by this particle.
+	 */
+	private double bestFitness = Double.NEGATIVE_INFINITY;
+
+	/**
+	 * Instantiates a new Particle.
+	 *
+	 * @param initialPosition
+	 *            the initial {@link #position}
+	 * @param initialSpeed
+	 *            the initial {@link #speed}
+	 */
+	public Particle(long[] initialPosition, long[] initialSpeed) {
+		this.position = initialPosition;
+		this.speed = initialSpeed;
+	}
+
+	/**
+	 * Gets the {@link #position}.
+	 *
+	 * @return the {@link #position}
+	 */
+	public long[] getPosition() {
+		return position;
+	}
+
+	/**
+	 * Gets the {@link #speed}.
+	 *
+	 * @return the {@link #speed}
+	 */
+	public long[] getSpeed() {
+		return speed;
+	}
+
+	/**
+	 * Gets the {@link #fitness}.
+	 *
+	 * @return the {@link #fitness}
+	 */
+	public double getFitness() {
+		return fitness;
+	}
+
+	/**
+	 * Gets the {@link #bestPosition}.
+	 *
+	 * @return the {@link #bestPosition}
+	 */
+	public long[] getBestPosition() {
+		return bestPosition;
+	}
+
+	/**
+	 * Gets the {@link #bestFitness}.
+	 *
+	 * @return the {@link #bestFitness}
+	 */
+	public double getBestFitness() {
+		return bestFitness;
+	}
+
+	/**
+	 * Sets the {@link #position}.
+	 *
+	 * @param position
+	 *            the new {@link #position}
+	 */
+	public void setPosition(long[] position) {
+		this.position = position;
+	}
+
+	/**
+	 * Sets the {@link #speed}.
+	 *
+	 * @param speed
+	 *            the new {@link #speed}
+	 */
+	public void setSpeed(long[] speed) {
+		this.speed = speed;
+	}
+
+	/**
+	 * Sets the {@link #fitness}.
+	 *
+	 * @param fitness
+	 *            the new {@link #fitness}
+	 */
+	public void setFitness(double fitness) {
+		this.fitness = fitness;
+	}
+
+	/**
+	 * Sets the {@link #bestPosition}.
+	 *
+	 * @param bestPosition
+	 *            the new {@link #bestPosition}
+	 */
+	public void setBestPosition(long[] bestPosition) {
+		this.bestPosition = bestPosition;
+	}
+
+	/**
+	 * Sets the {@link #bestFitness}.
+	 *
+	 * @param bestFitness
+	 *            the new {@link #bestFitness}
+	 */
+	public void setBestFitness(double bestFitness) {
+		this.bestFitness = bestFitness;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see java.lang.Object#hashCode()
+	 */
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		long temp;
+		temp = Double.doubleToLongBits(bestFitness);
+		result = prime * result + (int) (temp ^ (temp >>> 32));
+		result = prime * result + Arrays.hashCode(bestPosition);
+		temp = Double.doubleToLongBits(fitness);
+		result = prime * result + (int) (temp ^ (temp >>> 32));
+		result = prime * result + Arrays.hashCode(position);
+		result = prime * result + Arrays.hashCode(speed);
+		return result;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see java.lang.Object#equals(java.lang.Object)
+	 */
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null)
+			return false;
+		if (getClass() != obj.getClass())
+			return false;
+		Particle other = (Particle) obj;
+		if (Double.doubleToLongBits(bestFitness) != Double.doubleToLongBits(other.bestFitness))
+			return false;
+		if (!Arrays.equals(bestPosition, other.bestPosition))
+			return false;
+		if (Double.doubleToLongBits(fitness) != Double.doubleToLongBits(other.fitness))
+			return false;
+		if (!Arrays.equals(position, other.position))
+			return false;
+		if (!Arrays.equals(speed, other.speed))
+			return false;
+		return true;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see java.lang.Object#toString()
+	 */
+	@Override
+	public String toString() {
+		return "Particle [position=" + Arrays.toString(position) + ", speed=" + Arrays.toString(speed) + ", fitness="
+				+ fitness + ", bestPosition=" + Arrays.toString(bestPosition) + ", bestFitness=" + bestFitness + "]";
+	}
+
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/multiswarm/Swarm.java

@@ -0,0 +1,155 @@
+package com.baeldung.algorithms.multiswarm;
+
+import java.util.Arrays;
+import java.util.Random;
+
+/**
+ * Represents a collection of {@link Particle}.
+ * 
+ * @author Donato Rimenti
+ *
+ */
+public class Swarm {
+
+	/**
+	 * The particles of this swarm.
+	 */
+	private Particle[] particles;
+
+	/**
+	 * The best position found within the particles of this swarm.
+	 */
+	private long[] bestPosition;
+
+	/**
+	 * The best fitness score found within the particles of this swarm.
+	 */
+	private double bestFitness = Double.NEGATIVE_INFINITY;
+
+	/**
+	 * A random generator.
+	 */
+	private Random random = new Random();
+
+	/**
+	 * Instantiates a new Swarm.
+	 *
+	 * @param numParticles
+	 *            the number of particles of the swarm
+	 */
+	public Swarm(int numParticles) {
+		particles = new Particle[numParticles];
+		for (int i = 0; i < numParticles; i++) {
+			long[] initialParticlePosition = { random.nextInt(Constants.PARTICLE_UPPER_BOUND),
+					random.nextInt(Constants.PARTICLE_UPPER_BOUND) };
+			long[] initialParticleSpeed = { random.nextInt(Constants.PARTICLE_UPPER_BOUND),
+					random.nextInt(Constants.PARTICLE_UPPER_BOUND) };
+			particles[i] = new Particle(initialParticlePosition, initialParticleSpeed);
+		}
+	}
+
+	/**
+	 * Gets the {@link #particles}.
+	 *
+	 * @return the {@link #particles}
+	 */
+	public Particle[] getParticles() {
+		return particles;
+	}
+
+	/**
+	 * Gets the {@link #bestPosition}.
+	 *
+	 * @return the {@link #bestPosition}
+	 */
+	public long[] getBestPosition() {
+		return bestPosition;
+	}
+
+	/**
+	 * Gets the {@link #bestFitness}.
+	 *
+	 * @return the {@link #bestFitness}
+	 */
+	public double getBestFitness() {
+		return bestFitness;
+	}
+
+	/**
+	 * Sets the {@link #bestPosition}.
+	 *
+	 * @param bestPosition
+	 *            the new {@link #bestPosition}
+	 */
+	public void setBestPosition(long[] bestPosition) {
+		this.bestPosition = bestPosition;
+	}
+
+	/**
+	 * Sets the {@link #bestFitness}.
+	 *
+	 * @param bestFitness
+	 *            the new {@link #bestFitness}
+	 */
+	public void setBestFitness(double bestFitness) {
+		this.bestFitness = bestFitness;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see java.lang.Object#hashCode()
+	 */
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		long temp;
+		temp = Double.doubleToLongBits(bestFitness);
+		result = prime * result + (int) (temp ^ (temp >>> 32));
+		result = prime * result + Arrays.hashCode(bestPosition);
+		result = prime * result + Arrays.hashCode(particles);
+		result = prime * result + ((random == null) ? 0 : random.hashCode());
+		return result;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see java.lang.Object#equals(java.lang.Object)
+	 */
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj)
+			return true;
+		if (obj == null)
+			return false;
+		if (getClass() != obj.getClass())
+			return false;
+		Swarm other = (Swarm) obj;
+		if (Double.doubleToLongBits(bestFitness) != Double.doubleToLongBits(other.bestFitness))
+			return false;
+		if (!Arrays.equals(bestPosition, other.bestPosition))
+			return false;
+		if (!Arrays.equals(particles, other.particles))
+			return false;
+		if (random == null) {
+			if (other.random != null)
+				return false;
+		} else if (!random.equals(other.random))
+			return false;
+		return true;
+	}
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see java.lang.Object#toString()
+	 */
+	@Override
+	public String toString() {
+		return "Swarm [particles=" + Arrays.toString(particles) + ", bestPosition=" + Arrays.toString(bestPosition)
+				+ ", bestFitness=" + bestFitness + ", random=" + random + "]";
+	}
+
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/permutation/Permutation.java

@@ -0,0 +1,123 @@
+package com.baeldung.algorithms.permutation;
+
+import java.util.Arrays;
+import java.util.Collections;
+
+public  class Permutation {
+
+    public static <T> void printAllRecursive(T[] elements, char delimiter) {
+        printAllRecursive(elements.length, elements, delimiter);
+    }
+
+    public static <T> void printAllRecursive(int n, T[] elements, char delimiter) {
+
+        if(n == 1) {
+            printArray(elements, delimiter);
+        } else {
+            for(int i = 0; i < n-1; i++) {
+                printAllRecursive(n - 1, elements, delimiter);
+                if(n % 2 == 0) {
+                    swap(elements, i, n-1);
+                } else {
+                    swap(elements, 0, n-1);
+                }
+            }
+            printAllRecursive(n - 1, elements, delimiter);
+        }
+    }
+
+    public static <T> void printAllIterative(int n, T[] elements, char delimiter) {
+
+        int[] indexes = new int[n];
+        for (int i = 0; i < n; i++) {
+            indexes[i] = 0;
+        }
+
+        printArray(elements, delimiter);
+
+        int i = 0;
+        while (i < n) {
+            if (indexes[i] < i) {
+                swap(elements, i % 2 == 0 ?  0: indexes[i], i);
+                printArray(elements, delimiter);
+                indexes[i]++;
+                i = 0;
+            }
+            else {
+                indexes[i] = 0;
+                i++;
+            }
+        }
+    }
+
+    public static <T extends Comparable<T>> void printAllOrdered(T[] elements, char delimiter) {
+
+        Arrays.sort(elements);
+        boolean hasNext = true;
+
+        while(hasNext) {
+            printArray(elements, delimiter);
+            int k = 0, l = 0;
+            hasNext = false;
+            for (int i = elements.length - 1; i > 0; i--) {
+                if (elements[i].compareTo(elements[i - 1]) > 0) {
+                    k = i - 1;
+                    hasNext = true;
+                    break;
+                }
+            }
+
+            for (int i = elements.length - 1; i > k; i--) {
+                if (elements[i].compareTo(elements[k]) > 0) {
+                    l = i;
+                    break;
+                }
+            }
+
+            swap(elements, k, l);
+            Collections.reverse(Arrays.asList(elements).subList(k + 1, elements.length));
+        }
+    }
+
+    public static <T> void printRandom(T[] elements, char delimiter) {
+
+        Collections.shuffle(Arrays.asList(elements));
+        printArray(elements, delimiter);
+    }
+
+    private static <T> void swap(T[] elements, int a, int b) {
+
+        T tmp = elements[a];
+        elements[a] = elements[b];
+        elements[b] = tmp;
+    }
+
+    private static <T> void printArray(T[] elements, char delimiter) {
+
+        String delimiterSpace = delimiter + " ";
+        for(int i = 0; i < elements.length; i++) {
+            System.out.print(elements[i] + delimiterSpace);
+        }
+        System.out.print('\n');
+    }
+
+    public static void main(String[] argv) {
+
+        Integer[] elements = {1,2,3,4};
+
+        System.out.println("Rec:");
+        printAllRecursive(elements, ';');
+
+        System.out.println("Iter:");
+        printAllIterative(elements.length, elements, ';');
+
+        System.out.println("Orderes:");
+        printAllOrdered(elements, ';');
+
+        System.out.println("Random:");
+        printRandom(elements, ';');
+
+        System.out.println("Random:");
+        printRandom(elements, ';');
+    }
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/string/EnglishAlphabetLetters.java

@@ -0,0 +1,35 @@
+package com.baeldung.algorithms.string;
+
+public class EnglishAlphabetLetters {
+
+    public static boolean checkStringForAllTheLetters(String input) {
+        boolean[] visited = new boolean[26];
+
+        int index = 0;
+
+        for (int id = 0; id < input.length(); id++) {
+            if ('a' <= input.charAt(id) && input.charAt(id) <= 'z') {
+                index = input.charAt(id) - 'a';
+            } else if ('A' <= input.charAt(id) && input.charAt(id) <= 'Z') {
+                index = input.charAt(id) - 'A';
+            }
+            visited[index] = true;
+        }
+
+        for (int id = 0; id < 26; id++) {
+            if (!visited[id]) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    public static boolean checkStringForAllLetterUsingStream(String input) {
+        long c = input.toLowerCase().chars().filter(ch -> ch >= 'a' && ch <= 'z').distinct().count();
+        return c == 26;
+    }
+
+    public static void main(String[] args) {
+        checkStringForAllLetterUsingStream("intit");
+    }
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/string/LongestSubstringNonRepeatingCharacters.java

@@ -0,0 +1,54 @@
+package com.baeldung.algorithms.string;
+
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
+
+public class LongestSubstringNonRepeatingCharacters {
+
+    public static String getUniqueCharacterSubstringBruteForce(String input) {
+        String output = "";
+        for (int start = 0; start < input.length(); start++) {
+            Set<Character> visited = new HashSet<>();
+            int end = start;
+            for (; end < input.length(); end++) {
+                char currChar = input.charAt(end);
+                if (visited.contains(currChar)) {
+                    break;
+                } else {
+                    visited.add(currChar);
+                }
+            }
+            if (output.length() < end - start + 1) {
+                output = input.substring(start, end);
+            }
+        }
+        return output;
+    }
+
+    public static String getUniqueCharacterSubstring(String input) {
+        Map<Character, Integer> visited = new HashMap<>();
+        String output = "";
+        for (int start = 0, end = 0; end < input.length(); end++) {
+            char currChar = input.charAt(end);
+            if (visited.containsKey(currChar)) {
+                start = Math.max(visited.get(currChar) + 1, start);
+            }
+            if (output.length() < end - start + 1) {
+                output = input.substring(start, end + 1);
+            }
+            visited.put(currChar, end);
+        }
+        return output;
+    }
+
+    public static void main(String[] args) {
+        if(args.length > 0) {
+            System.out.println(getUniqueCharacterSubstring(args[0]));
+        } else {
+            System.err.println("This program expects command-line input. Please try again!");
+        }
+    }
+
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/string/SubstringPalindrome.java

@@ -0,0 +1,90 @@
+package com.baeldung.algorithms.string;
+
+import java.util.HashSet;
+import java.util.Set;
+
+public class SubstringPalindrome {
+
+    public Set<String> findAllPalindromesUsingCenter(String input) {
+        final Set<String> palindromes = new HashSet<>();
+        if (input == null || input.isEmpty()) {
+            return palindromes;
+        }
+        if (input.length() == 1) {
+            palindromes.add(input);
+            return palindromes;
+        }
+        for (int i = 0; i < input.length(); i++) {
+            palindromes.addAll(findPalindromes(input, i, i + 1));
+            palindromes.addAll(findPalindromes(input, i, i));
+        }
+        return palindromes;
+    }
+
+    private Set<String> findPalindromes(String input, int low, int high) {
+        Set<String> result = new HashSet<>();
+        while (low >= 0 && high < input.length() && input.charAt(low) == input.charAt(high)) {
+            result.add(input.substring(low, high + 1));
+            low--;
+            high++;
+        }
+        return result;
+    }
+
+    public Set<String> findAllPalindromesUsingBruteForceApproach(String input) {
+        Set<String> palindromes = new HashSet<>();
+        if (input == null || input.isEmpty()) {
+            return palindromes;
+        }
+        if (input.length() == 1) {
+            palindromes.add(input);
+            return palindromes;
+        }
+        for (int i = 0; i < input.length(); i++) {
+            for (int j = i + 1; j <= input.length(); j++)
+                if (isPalindrome(input.substring(i, j))) {
+                    palindromes.add(input.substring(i, j));
+                }
+        }
+        return palindromes;
+    }
+
+    private boolean isPalindrome(String input) {
+        StringBuilder plain = new StringBuilder(input);
+        StringBuilder reverse = plain.reverse();
+        return (reverse.toString()).equals(input);
+    }
+
+    public Set<String> findAllPalindromesUsingManachersAlgorithm(String input) {
+        Set<String> palindromes = new HashSet<>();
+        String formattedInput = "@" + input + "#";
+        char inputCharArr[] = formattedInput.toCharArray();
+        int max;
+        int radius[][] = new int[2][input.length() + 1];
+        for (int j = 0; j <= 1; j++) {
+            radius[j][0] = max = 0;
+            int i = 1;
+            while (i <= input.length()) {
+                palindromes.add(Character.toString(inputCharArr[i]));
+                while (inputCharArr[i - max - 1] == inputCharArr[i + j + max])
+                    max++;
+                radius[j][i] = max;
+                int k = 1;
+                while ((radius[j][i - k] != max - k) && (k < max)) {
+                    radius[j][i + k] = Math.min(radius[j][i - k], max - k);
+                    k++;
+                }
+                max = Math.max(max - k, 0);
+                i += k;
+            }
+        }
+        for (int i = 1; i <= input.length(); i++) {
+            for (int j = 0; j <= 1; j++) {
+                for (max = radius[j][i]; max > 0; max--) {
+                    palindromes.add(input.substring(i - max - 1, max + j + i - 1));
+                }
+            }
+        }
+        return palindromes;
+    }
+}

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/string/search/StringSearchAlgorithms.java

@@ -0,0 +1,194 @@
+package com.baeldung.algorithms.string.search;
+
+import java.math.BigInteger;
+import java.util.Random;
+
+public class StringSearchAlgorithms {
+    public static long getBiggerPrime(int m) {
+        BigInteger prime = BigInteger.probablePrime(getNumberOfBits(m) + 1, new Random());
+        return prime.longValue();
+    }
+
+    public static long getLowerPrime(long number) {
+        BigInteger prime = BigInteger.probablePrime(getNumberOfBits(number) - 1, new Random());
+        return prime.longValue();
+    }
+
+    private static int getNumberOfBits(final int number) {
+        return Integer.SIZE - Integer.numberOfLeadingZeros(number);
+    }
+
+    private static int getNumberOfBits(final long number) {
+        return Long.SIZE - Long.numberOfLeadingZeros(number);
+    }
+
+    public static int simpleTextSearch(char[] pattern, char[] text) {
+        int patternSize = pattern.length;
+        int textSize = text.length;
+
+        int i = 0;
+
+        while ((i + patternSize) <= textSize) {
+            int j = 0;
+            while (text[i + j] == pattern[j]) {
+                j += 1;
+                if (j >= patternSize)
+                    return i;
+            }
+            i += 1;
+        }
+
+        return -1;
+    }
+
+    public static int RabinKarpMethod(char[] pattern, char[] text) {
+        int patternSize = pattern.length; // m
+        int textSize = text.length; // n
+
+        long prime = getBiggerPrime(patternSize);
+
+        long r = 1;
+        for (int i = 0; i < patternSize - 1; i++) {
+            r *= 2;
+            r = r % prime;
+        }
+
+        long[] t = new long[textSize];
+        t[0] = 0;
+
+        long pfinger = 0;
+
+        for (int j = 0; j < patternSize; j++) {
+            t[0] = (2 * t[0] + text[j]) % prime;
+            pfinger = (2 * pfinger + pattern[j]) % prime;
+        }
+
+        int i = 0;
+        boolean passed = false;
+
+        int diff = textSize - patternSize;
+        for (i = 0; i <= diff; i++) {
+            if (t[i] == pfinger) {
+                passed = true;
+                for (int k = 0; k < patternSize; k++) {
+                    if (text[i + k] != pattern[k]) {
+                        passed = false;
+                        break;
+                    }
+                }
+
+                if (passed) {
+                    return i;
+                }
+            }
+
+            if (i < diff) {
+                long value = 2 * (t[i] - r * text[i]) + text[i + patternSize];
+                t[i + 1] = ((value % prime) + prime) % prime;
+            }
+        }
+        return -1;
+
+    }
+
+    public static int KnuthMorrisPrattSearch(char[] pattern, char[] text) {
+        int patternSize = pattern.length; // m
+        int textSize = text.length; // n
+
+        int i = 0, j = 0;
+
+        int[] shift = KnuthMorrisPrattShift(pattern);
+
+        while ((i + patternSize) <= textSize) {
+            while (text[i + j] == pattern[j]) {
+                j += 1;
+                if (j >= patternSize)
+                    return i;
+            }
+
+            if (j > 0) {
+                i += shift[j - 1];
+                j = Math.max(j - shift[j - 1], 0);
+            } else {
+                i++;
+                j = 0;
+            }
+        }
+        return -1;
+    }
+
+    public static int[] KnuthMorrisPrattShift(char[] pattern) {
+        int patternSize = pattern.length;
+
+        int[] shift = new int[patternSize];
+        shift[0] = 1;
+
+        int i = 1, j = 0;
+
+        while ((i + j) < patternSize) {
+            if (pattern[i + j] == pattern[j]) {
+                shift[i + j] = i;
+                j++;
+            } else {
+                if (j == 0)
+                    shift[i] = i + 1;
+
+                if (j > 0) {
+                    i = i + shift[j - 1];
+                    j = Math.max(j - shift[j - 1], 0);
+                } else {
+                    i = i + 1;
+                    j = 0;
+                }
+            }
+        }
+        return shift;
+    }
+
+    public static int BoyerMooreHorspoolSimpleSearch(char[] pattern, char[] text) {
+        int patternSize = pattern.length;
+        int textSize = text.length;
+
+        int i = 0, j = 0;
+
+        while ((i + patternSize) <= textSize) {
+            j = patternSize - 1;
+            while (text[i + j] == pattern[j]) {
+                j--;
+                if (j < 0)
+                    return i;
+            }
+            i++;
+        }
+        return -1;
+    }
+
+    public static int BoyerMooreHorspoolSearch(char[] pattern, char[] text) {
+
+        int shift[] = new int[256];
+
+        for (int k = 0; k < 256; k++) {
+            shift[k] = pattern.length;
+        }
+
+        for (int k = 0; k < pattern.length - 1; k++) {
+            shift[pattern[k]] = pattern.length - 1 - k;
+        }
+
+        int i = 0, j = 0;
+
+        while ((i + pattern.length) <= text.length) {
+            j = pattern.length - 1;
+
+            while (text[i + j] == pattern[j]) {
+                j -= 1;
+                if (j < 0)
+                    return i;
+            }
+
+            i = i + shift[text[i + pattern.length - 1]];
+
+        }
+        return -1;
+    }
+}

algorithms-miscellaneous-1/src/main/resources/logback.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

algorithms-miscellaneous-1/src/test/java/com/baeldung/algorithms/HillClimbingAlgorithmUnitTest.java

@@ -0,0 +1,58 @@
+package com.baeldung.algorithms;
+
+import com.baeldung.algorithms.hillclimbing.HillClimbing;
+import com.baeldung.algorithms.hillclimbing.State;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Stack;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+public class HillClimbingAlgorithmUnitTest {
+    private Stack<String> initStack;
+    private Stack<String> goalStack;
+
+    @Before
+    public void initStacks() {
+        String blockArr[] = { "B", "C", "D", "A" };
+        String goalBlockArr[] = { "A", "B", "C", "D" };
+        initStack = new Stack<>();
+        for (String block : blockArr)
+            initStack.push(block);
+        goalStack = new Stack<>();
+        for (String block : goalBlockArr)
+            goalStack.push(block);
+    }
+
+    @Test
+    public void givenInitAndGoalState_whenGetPathWithHillClimbing_thenPathFound() {
+        HillClimbing hillClimbing = new HillClimbing();
+
+        List<State> path;
+        try {
+            path = hillClimbing.getRouteWithHillClimbing(initStack, goalStack);
+            assertNotNull(path);
+            assertEquals(path.get(path.size() - 1)
+                .getState()
+                .get(0), goalStack);
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+    @Test
+    public void givenCurrentState_whenFindNextState_thenBetterHeuristics() {
+        HillClimbing hillClimbing = new HillClimbing();
+        List<Stack<String>> initList = new ArrayList<>();
+        initList.add(initStack);
+        State currentState = new State(initList);
+        currentState.setHeuristics(hillClimbing.getHeuristicsValue(initList, goalStack));
+        State nextState = hillClimbing.findNextState(currentState, goalStack);
+        assertTrue(nextState.getHeuristics() > currentState.getHeuristics());
+    }
+}

algorithms-miscellaneous-1/src/test/java/com/baeldung/algorithms/MiddleElementLookupUnitTest.java

@@ -0,0 +1,118 @@
+package com.baeldung.algorithms;
+
+import com.baeldung.algorithms.middleelementlookup.MiddleElementLookup;
+import com.baeldung.algorithms.middleelementlookup.Node;
+import org.junit.Test;
+
+import java.util.LinkedList;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+
+public class MiddleElementLookupUnitTest {
+
+    @Test
+    public void whenFindingMiddleLinkedList_thenMiddleFound() {
+        assertEquals("3", MiddleElementLookup
+          .findMiddleElementLinkedList(createLinkedList(5))
+          .get());
+        assertEquals("2", MiddleElementLookup
+          .findMiddleElementLinkedList(createLinkedList(4))
+          .get());
+    }
+
+    @Test
+    public void whenFindingMiddleFromHead_thenMiddleFound() {
+        assertEquals("3", MiddleElementLookup
+          .findMiddleElementFromHead(createNodesList(5))
+          .get());
+        assertEquals("2", MiddleElementLookup
+          .findMiddleElementFromHead(createNodesList(4))
+          .get());
+    }
+
+    @Test
+    public void whenFindingMiddleFromHead1PassRecursively_thenMiddleFound() {
+        assertEquals("3", MiddleElementLookup
+          .findMiddleElementFromHead1PassRecursively(createNodesList(5))
+          .get());
+        assertEquals("2", MiddleElementLookup
+          .findMiddleElementFromHead1PassRecursively(createNodesList(4))
+          .get());
+    }
+
+    @Test
+    public void whenFindingMiddleFromHead1PassIteratively_thenMiddleFound() {
+        assertEquals("3", MiddleElementLookup
+          .findMiddleElementFromHead1PassIteratively(createNodesList(5))
+          .get());
+        assertEquals("2", MiddleElementLookup
+          .findMiddleElementFromHead1PassIteratively(createNodesList(4))
+          .get());
+    }
+
+    @Test
+    public void whenListEmptyOrNull_thenMiddleNotFound() {
+        // null list
+        assertFalse(MiddleElementLookup
+          .findMiddleElementLinkedList(null)
+          .isPresent());
+        assertFalse(MiddleElementLookup
+          .findMiddleElementFromHead(null)
+          .isPresent());
+        assertFalse(MiddleElementLookup
+          .findMiddleElementFromHead1PassIteratively(null)
+          .isPresent());
+        assertFalse(MiddleElementLookup
+          .findMiddleElementFromHead1PassRecursively(null)
+          .isPresent());
+
+        // empty LinkedList
+        assertFalse(MiddleElementLookup
+          .findMiddleElementLinkedList(new LinkedList<>())
+          .isPresent());
+
+        // LinkedList with nulls
+        LinkedList<String> nullsList = new LinkedList<>();
+        nullsList.add(null);
+        nullsList.add(null);
+        assertFalse(MiddleElementLookup
+          .findMiddleElementLinkedList(nullsList)
+          .isPresent());
+
+        // nodes with null values
+        assertFalse(MiddleElementLookup
+          .findMiddleElementFromHead(new Node(null))
+          .isPresent());
+        assertFalse(MiddleElementLookup
+          .findMiddleElementFromHead1PassIteratively(new Node(null))
+          .isPresent());
+        assertFalse(MiddleElementLookup
+          .findMiddleElementFromHead1PassRecursively(new Node(null))
+          .isPresent());
+    }
+
+    private static LinkedList<String> createLinkedList(int n) {
+        LinkedList<String> list = new LinkedList<>();
+
+        for (int i = 1; i <= n; i++) {
+            list.add(String.valueOf(i));
+        }
+
+        return list;
+    }
+
+    private static Node createNodesList(int n) {
+        Node head = new Node("1");
+        Node current = head;
+
+        for (int i = 2; i <= n; i++) {
+            Node newNode = new Node(String.valueOf(i));
+            current.setNext(newNode);
+            current = newNode;
+        }
+
+        return head;
+    }
+
+}

algorithms-miscellaneous-1/src/test/java/com/baeldung/algorithms/RtFiniteStateMachineLongRunningUnitTest.java

@@ -0,0 +1,73 @@
+package com.baeldung.algorithms;
+
+import com.baeldung.algorithms.automata.*;
+import org.junit.Test;
+
+import static org.junit.Assert.assertTrue;
+
+public final class RtFiniteStateMachineLongRunningUnitTest {
+
+    @Test
+    public void acceptsSimplePair() {
+        String json = "{\"key\":\"value\"}";
+        FiniteStateMachine machine = this.buildJsonStateMachine();
+        for (int i = 0; i < json.length(); i++) {
+            machine = machine.switchState(String.valueOf(json.charAt(i)));
+        }
+        assertTrue(machine.canStop());
+    }
+
+    @Test
+    public void acceptsMorePairs() {
+        String json = "{\"key1\":\"value1\",\"key2\":\"value2\"}";
+        FiniteStateMachine machine = this.buildJsonStateMachine();
+        for (int i = 0; i < json.length(); i++) {
+            machine = machine.switchState(String.valueOf(json.charAt(i)));
+        }
+        assertTrue(machine.canStop());
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void missingColon() {
+        String json = "{\"key\"\"value\"}";
+        FiniteStateMachine machine = this.buildJsonStateMachine();
+        for (int i = 0; i < json.length(); i++) {
+            machine = machine.switchState(String.valueOf(json.charAt(i)));
+        }
+    }
+
+    /**
+     * Builds a finite state machine to validate a simple
+     * Json object.
+     * @return
+     */
+    private FiniteStateMachine buildJsonStateMachine() {
+        State first = new RtState();
+        State second = new RtState();
+        State third = new RtState();
+        State fourth = new RtState();
+        State fifth = new RtState();
+        State sixth = new RtState();
+        State seventh = new RtState();
+        State eighth = new RtState(true);
+
+        first.with(new RtTransition("{", second));
+        second.with(new RtTransition("\"", third));
+        //Add transitions with chars 0-9 and a-z
+        for (int i = 0; i < 26; i++) {
+            if (i < 10) {
+                third = third.with(new RtTransition(String.valueOf(i), third));
+                sixth = sixth.with(new RtTransition(String.valueOf(i), sixth));
+            }
+            third = third.with(new RtTransition(String.valueOf((char) ('a' + i)), third));
+            sixth = sixth.with(new RtTransition(String.valueOf((char) ('a' + i)), sixth));
+        }
+        third.with(new RtTransition("\"", fourth));
+        fourth.with(new RtTransition(":", fifth));
+        fifth.with(new RtTransition("\"", sixth));
+        sixth.with(new RtTransition("\"", seventh));
+        seventh.with(new RtTransition(",", second));
+        seventh.with(new RtTransition("}", eighth));
+        return new RtFiniteStateMachine(first);
+    }
+}

algorithms-miscellaneous-1/src/test/java/com/baeldung/algorithms/StringSearchAlgorithmsUnitTest.java

@@ -0,0 +1,25 @@
+package com.baeldung.algorithms;
+
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import com.baeldung.algorithms.string.search.StringSearchAlgorithms;
+
+public class StringSearchAlgorithmsUnitTest {
+	
+	
+	@Test
+	public void testStringSearchAlgorithms(){
+		String text = "This is some nice text.";
+		String pattern = "some";
+		
+		int realPosition = text.indexOf(pattern);
+        Assert.assertTrue(realPosition == StringSearchAlgorithms.simpleTextSearch(pattern.toCharArray(), text.toCharArray()));
+        Assert.assertTrue(realPosition == StringSearchAlgorithms.RabinKarpMethod(pattern.toCharArray(), text.toCharArray()));
+        Assert.assertTrue(realPosition == StringSearchAlgorithms.KnuthMorrisPrattSearch(pattern.toCharArray(), text.toCharArray()));
+        Assert.assertTrue(realPosition == StringSearchAlgorithms.BoyerMooreHorspoolSimpleSearch(pattern.toCharArray(), text.toCharArray()));
+        Assert.assertTrue(realPosition == StringSearchAlgorithms.BoyerMooreHorspoolSearch(pattern.toCharArray(), text.toCharArray()));
+	}
+
+}

algorithms-miscellaneous-1/src/test/java/com/baeldung/algorithms/binarysearch/BinarySearchUnitTest.java

@@ -0,0 +1,43 @@
+package com.baeldung.algorithms.binarysearch;
+
+import java.util.Arrays;
+import java.util.List;
+
+import org.junit.Assert;
+import org.junit.Test;
+import com.baeldung.algorithms.binarysearch.BinarySearch;
+
+public class BinarySearchUnitTest {
+
+    int[] sortedArray = { 0, 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 9 };
+    int key = 6;
+    int expectedIndexForSearchKey = 7;
+    int low = 0;
+    int high = sortedArray.length - 1;
+    List<Integer> sortedList = Arrays.asList(0, 1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 9);
+    
+    @Test
+    public void givenASortedArrayOfIntegers_whenBinarySearchRunIterativelyForANumber_thenGetIndexOfTheNumber() {
+        BinarySearch binSearch = new BinarySearch();
+        Assert.assertEquals(expectedIndexForSearchKey, binSearch.runBinarySearchIteratively(sortedArray, key, low, high));
+    }
+
+    @Test
+    public void givenASortedArrayOfIntegers_whenBinarySearchRunRecursivelyForANumber_thenGetIndexOfTheNumber() {
+        BinarySearch binSearch = new BinarySearch();
+        Assert.assertEquals(expectedIndexForSearchKey, binSearch.runBinarySearchRecursively(sortedArray, key, low, high));
+    }
+    
+    @Test
+    public void givenASortedArrayOfIntegers_whenBinarySearchRunUsingArraysClassStaticMethodForANumber_thenGetIndexOfTheNumber() {
+        BinarySearch binSearch = new BinarySearch();
+        Assert.assertEquals(expectedIndexForSearchKey, binSearch.runBinarySearchUsingJavaArrays(sortedArray, key));
+    }
+    
+    @Test
+    public void givenASortedListOfIntegers_whenBinarySearchRunUsingCollectionsClassStaticMethodForANumber_thenGetIndexOfTheNumber() {
+        BinarySearch binSearch = new BinarySearch();
+        Assert.assertEquals(expectedIndexForSearchKey, binSearch.runBinarySearchUsingJavaCollections(sortedList, key));
+    }
+    
+}

algorithms-miscellaneous-1/src/test/java/com/baeldung/algorithms/kthlargest/FindKthLargestUnitTest.java

@@ -0,0 +1,57 @@
+package com.baeldung.algorithms.kthlargest;
+
+import static org.assertj.core.api.Assertions.*;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class FindKthLargestUnitTest {
+
+    private FindKthLargest findKthLargest;
+    private Integer[] arr = { 3, 7, 1, 2, 8, 10, 4, 5, 6, 9 };
+
+    @Before
+    public void setup() {
+        findKthLargest = new FindKthLargest();
+    }
+
+    @Test
+    public void givenIntArray_whenFindKthLargestBySorting_thenGetResult() {
+        int k = 3;
+        assertThat(findKthLargest.findKthLargestBySorting(arr, k)).isEqualTo(8);
+    }
+
+    @Test
+    public void givenIntArray_whenFindKthLargestBySortingDesc_thenGetResult() {
+        int k = 3;
+        assertThat(findKthLargest.findKthLargestBySortingDesc(arr, k)).isEqualTo(8);
+    }
+
+    @Test
+    public void givenIntArray_whenFindKthLargestByQuickSelect_thenGetResult() {
+        int k = 3;
+        int kthLargest = arr.length - k;
+        assertThat(findKthLargest.findKthElementByQuickSelect(arr, 0, arr.length - 1, kthLargest)).isEqualTo(8);
+    }
+
+    @Test
+    public void givenIntArray_whenFindKthElementByQuickSelectIterative_thenGetResult() {
+        int k = 3;
+        int kthLargest = arr.length - k;
+        assertThat(findKthLargest.findKthElementByQuickSelectWithIterativePartition(arr, 0, arr.length - 1, kthLargest)).isEqualTo(8);
+    }
+
+    @Test
+    public void givenIntArray_whenFindKthSmallestByQuickSelect_thenGetResult() {
+        int k = 3;
+        assertThat(findKthLargest.findKthElementByQuickSelect(arr, 0, arr.length - 1, k - 1)).isEqualTo(3);
+    }
+
+    @Test
+    public void givenIntArray_whenFindKthLargestByRandomizedQuickSelect_thenGetResult() {
+        int k = 3;
+        int kthLargest = arr.length - k;
+        assertThat(findKthLargest.findKthElementByRandomizedQuickSelect(arr, 0, arr.length - 1, kthLargest)).isEqualTo(8);
+    }
+
+}

algorithms-miscellaneous-1/src/test/java/com/baeldung/algorithms/mcts/MCTSUnitTest.java

@@ -0,0 +1,92 @@
+package com.baeldung.algorithms.mcts;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.util.List;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import com.baeldung.algorithms.mcts.montecarlo.MonteCarloTreeSearch;
+import com.baeldung.algorithms.mcts.montecarlo.State;
+import com.baeldung.algorithms.mcts.montecarlo.UCT;
+import com.baeldung.algorithms.mcts.tictactoe.Board;
+import com.baeldung.algorithms.mcts.tictactoe.Position;
+import com.baeldung.algorithms.mcts.tree.Tree;
+
+public class MCTSUnitTest {
+    private Tree gameTree;
+    private MonteCarloTreeSearch mcts;
+
+    @Before
+    public void initGameTree() {
+        gameTree = new Tree();
+        mcts = new MonteCarloTreeSearch();
+    }
+
+    @Test
+    public void givenStats_whenGetUCTForNode_thenUCTMatchesWithManualData() {
+        double uctValue = 15.79;
+        assertEquals(UCT.uctValue(600, 300, 20), uctValue, 0.01);
+    }
+
+    @Test
+    public void giveninitBoardState_whenGetAllPossibleStates_thenNonEmptyList() {
+        State initState = gameTree.getRoot().getState();
+        List<State> possibleStates = initState.getAllPossibleStates();
+        assertTrue(possibleStates.size() > 0);
+    }
+
+    @Test
+    public void givenEmptyBoard_whenPerformMove_thenLessAvailablePossitions() {
+        Board board = new Board();
+        int initAvailablePositions = board.getEmptyPositions().size();
+        board.performMove(Board.P1, new Position(1, 1));
+        int availablePositions = board.getEmptyPositions().size();
+        assertTrue(initAvailablePositions > availablePositions);
+    }
+
+    @Test
+    public void givenEmptyBoard_whenSimulateInterAIPlay_thenGameDraw() {
+        Board board = new Board();
+
+        int player = Board.P1;
+        int totalMoves = Board.DEFAULT_BOARD_SIZE * Board.DEFAULT_BOARD_SIZE;
+        for (int i = 0; i < totalMoves; i++) {
+            board = mcts.findNextMove(board, player);
+            if (board.checkStatus() != -1) {
+                break;
+            }
+            player = 3 - player;
+        }
+        int winStatus = board.checkStatus();
+        assertEquals(winStatus, Board.DRAW);
+    }
+
+    @Test
+    public void givenEmptyBoard_whenLevel1VsLevel3_thenLevel3WinsOrDraw() {
+        Board board = new Board();
+        MonteCarloTreeSearch mcts1 = new MonteCarloTreeSearch();
+        mcts1.setLevel(1);
+        MonteCarloTreeSearch mcts3 = new MonteCarloTreeSearch();
+        mcts3.setLevel(3);
+
+        int player = Board.P1;
+        int totalMoves = Board.DEFAULT_BOARD_SIZE * Board.DEFAULT_BOARD_SIZE;
+        for (int i = 0; i < totalMoves; i++) {
+            if (player == Board.P1)
+                board = mcts3.findNextMove(board, player);
+            else
+                board = mcts1.findNextMove(board, player);
+
+            if (board.checkStatus() != -1) {
+                break;
+            }
+            player = 3 - player;
+        }
+        int winStatus = board.checkStatus();
+        assertTrue(winStatus == Board.DRAW || winStatus == Board.P1);
+    }
+
+}

algorithms-miscellaneous-1/src/test/java/com/baeldung/algorithms/minimax/MinimaxUnitTest.java

@@ -0,0 +1,36 @@
+package com.baeldung.algorithms.minimax;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+import com.baeldung.algorithms.minimax.MiniMax;
+import com.baeldung.algorithms.minimax.Tree;
+
+public class MinimaxUnitTest {
+    private Tree gameTree;
+    private MiniMax miniMax;
+
+    @Before
+    public void initMiniMaxUtility() {
+        miniMax = new MiniMax();
+    }
+
+    @Test
+    public void givenMiniMax_whenConstructTree_thenNotNullTree() {
+        assertNull(gameTree);
+        miniMax.constructTree(6);
+        gameTree = miniMax.getTree();
+        assertNotNull(gameTree);
+    }
+
+    @Test
+    public void givenMiniMax_whenCheckWin_thenComputeOptimal() {
+        miniMax.constructTree(6);
+        boolean result = miniMax.checkWin();
+        assertTrue(result);
+        miniMax.constructTree(8);
+        result = miniMax.checkWin();
+        assertFalse(result);
+    }
+}

algorithms-miscellaneous-1/src/test/java/com/baeldung/algorithms/multiswarm/LolFitnessFunction.java

@@ -0,0 +1,52 @@
+package com.baeldung.algorithms.multiswarm;
+
+/**
+ * Specific fitness function implementation to solve the League of Legends
+ * problem. This is the problem statement: <br>
+ * <br>
+ * In League of Legends, a player's Effective Health when defending against
+ * physical damage is given by E=H(100+A)/100, where H is health and A is armor.
+ * Health costs 2.5 gold per unit, and Armor costs 18 gold per unit. You have
+ * 3600 gold, and you need to optimize the effectiveness E of your health and
+ * armor to survive as long as possible against the enemy team's attacks. How
+ * much of each should you buy? <br>
+ * <br>
+ * 
+ * @author Donato Rimenti
+ *
+ */
+public class LolFitnessFunction implements FitnessFunction {
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see
+	 * com.baeldung.algorithms.multiswarm.FitnessFunction#getFitness(long[])
+	 */
+	@Override
+	public double getFitness(long[] particlePosition) {
+
+		long health = particlePosition[0];
+		long armor = particlePosition[1];
+
+		// No negatives values accepted.
+		if (health < 0 && armor < 0) {
+			return -(health * armor);
+		} else if (health < 0) {
+			return health;
+		} else if (armor < 0) {
+			return armor;
+		}
+
+		// Checks if the solution is actually feasible provided our gold.
+		double cost = (health * 2.5) + (armor * 18);
+		if (cost > 3600) {
+			return 3600 - cost;
+		} else {
+			// Check how good is the solution.
+			long fitness = (health * (100 + armor)) / 100;
+			return fitness;
+		}
+	}
+
+}

algorithms-miscellaneous-1/src/test/java/com/baeldung/algorithms/multiswarm/MultiswarmUnitTest.java

@@ -0,0 +1,54 @@
+package com.baeldung.algorithms.multiswarm;
+
+import org.junit.Assert;
+import org.junit.Rule;
+import org.junit.Test;
+
+import com.baeldung.algorithms.support.MayFailRule;
+
+/**
+ * Test for {@link Multiswarm}.
+ * 
+ * @author Donato Rimenti
+ * 
+ */
+public class MultiswarmUnitTest {
+
+	/**
+	 * Rule for handling expected failures. We use this since this test may
+	 * actually fail due to bad luck in the random generation.
+	 */
+	@Rule
+	public MayFailRule mayFailRule = new MayFailRule();
+
+	/**
+	 * Tests the multiswarm algorithm with a generic problem. The problem is the
+	 * following: <br>
+	 * <br>
+	 * In League of Legends, a player's Effective Health when defending against
+	 * physical damage is given by E=H(100+A)/100, where H is health and A is
+	 * armor. Health costs 2.5 gold per unit, and Armor costs 18 gold per unit.
+	 * You have 3600 gold, and you need to optimize the effectiveness E of your
+	 * health and armor to survive as long as possible against the enemy team's
+	 * attacks. How much of each should you buy? <br>
+	 * <br>
+	 * The solution is H = 1080, A = 50 for a total fitness of 1620. Tested with
+	 * 50 swarms each with 1000 particles.
+	 */
+	@Test
+	public void givenMultiswarm_whenThousandIteration_thenSolutionFound() {
+		Multiswarm multiswarm = new Multiswarm(50, 1000, new LolFitnessFunction());
+
+		// Iterates 1000 times through the main loop and prints the result.
+		for (int i = 0; i < 1000; i++) {
+			multiswarm.mainLoop();
+		}
+
+		System.out.println("Best fitness found: " + multiswarm.getBestFitness() + "[" + multiswarm.getBestPosition()[0]
+				+ "," + multiswarm.getBestPosition()[1] + "]");
+		Assert.assertEquals(1080, multiswarm.getBestPosition()[0]);
+		Assert.assertEquals(50, multiswarm.getBestPosition()[1]);
+		Assert.assertEquals(1620, (int) multiswarm.getBestFitness());
+	}
+
+}

algorithms-miscellaneous-1/src/test/java/com/baeldung/algorithms/string/EnglishAlphabetLettersUnitTest.java

@@ -0,0 +1,20 @@
+package com.baeldung.algorithms.string;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class EnglishAlphabetLettersUnitTest {
+
+    @Test
+    void givenString_whenContainsAllCharacter_thenTrue() {
+        String input = "Farmer jack realized that big yellow quilts were expensive";
+        Assertions.assertTrue(EnglishAlphabetLetters.checkStringForAllTheLetters(input));
+    }
+
+    @Test
+    void givenString_whenContainsAllCharacter_thenUsingStreamExpectTrue() {
+        String input = "Farmer jack realized that big yellow quilts were expensive";
+        Assertions.assertTrue(EnglishAlphabetLetters.checkStringForAllLetterUsingStream(input));
+    }
+
+}

algorithms-miscellaneous-1/src/test/java/com/baeldung/algorithms/string/LongestSubstringNonRepeatingCharactersUnitTest.java

@@ -0,0 +1,31 @@
+package com.baeldung.algorithms.string;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static com.baeldung.algorithms.string.LongestSubstringNonRepeatingCharacters.getUniqueCharacterSubstring;
+import static com.baeldung.algorithms.string.LongestSubstringNonRepeatingCharacters.getUniqueCharacterSubstringBruteForce;
+
+public class LongestSubstringNonRepeatingCharactersUnitTest {
+
+    @Test
+    void givenString_whenGetUniqueCharacterSubstringBruteForceCalled_thenResultFoundAsExpectedUnitTest() {
+        assertEquals("", getUniqueCharacterSubstringBruteForce(""));
+        assertEquals("A", getUniqueCharacterSubstringBruteForce("A"));
+        assertEquals("ABCDEF", getUniqueCharacterSubstringBruteForce("AABCDEF"));
+        assertEquals("ABCDEF", getUniqueCharacterSubstringBruteForce("ABCDEFF"));
+        assertEquals("NGISAWE", getUniqueCharacterSubstringBruteForce("CODINGISAWESOME"));
+        assertEquals("be coding", getUniqueCharacterSubstringBruteForce("always be coding"));
+    }
+
+    @Test
+    void givenString_whenGetUniqueCharacterSubstringCalled_thenResultFoundAsExpectedUnitTest() {
+        assertEquals("", getUniqueCharacterSubstring(""));
+        assertEquals("A", getUniqueCharacterSubstring("A"));
+        assertEquals("ABCDEF", getUniqueCharacterSubstring("AABCDEF"));
+        assertEquals("ABCDEF", getUniqueCharacterSubstring("ABCDEFF"));
+        assertEquals("NGISAWE", getUniqueCharacterSubstring("CODINGISAWESOME"));
+        assertEquals("be coding", getUniqueCharacterSubstring("always be coding"));
+    }
+
+}

algorithms-miscellaneous-1/src/test/java/com/baeldung/algorithms/string/SubstringPalindromeUnitTest.java

@@ -0,0 +1,83 @@
+package com.baeldung.algorithms.string;
+
+import static org.junit.Assert.assertEquals;
+import java.util.HashSet;
+import java.util.Set;
+import org.junit.Test;
+
+public class SubstringPalindromeUnitTest {
+
+    private static final String INPUT_BUBBLE = "bubble";
+    private static final String INPUT_CIVIC = "civic";
+    private static final String INPUT_INDEED = "indeed";
+    private static final String INPUT_ABABAC = "ababac";
+
+    Set<String> EXPECTED_PALINDROME_BUBBLE = new HashSet<String>() {
+        {
+            add("b");
+            add("u");
+            add("l");
+            add("e");
+            add("bb");
+            add("bub");
+        }
+    };
+
+    Set<String> EXPECTED_PALINDROME_CIVIC = new HashSet<String>() {
+        {
+            add("civic");
+            add("ivi");
+            add("i");
+            add("c");
+            add("v");
+        }
+    };
+
+    Set<String> EXPECTED_PALINDROME_INDEED = new HashSet<String>() {
+        {
+            add("i");
+            add("n");
+            add("d");
+            add("e");
+            add("ee");
+            add("deed");
+        }
+    };
+
+    Set<String> EXPECTED_PALINDROME_ABABAC = new HashSet<String>() {
+        {
+            add("a");
+            add("b");
+            add("c");
+            add("aba");
+            add("bab");
+            add("ababa");
+        }
+    };
+
+    private SubstringPalindrome palindrome = new SubstringPalindrome();
+
+    @Test
+    public void whenUsingManachersAlgorithm_thenFindsAllPalindromes() {
+        assertEquals(EXPECTED_PALINDROME_BUBBLE, palindrome.findAllPalindromesUsingManachersAlgorithm(INPUT_BUBBLE));
+        assertEquals(EXPECTED_PALINDROME_INDEED, palindrome.findAllPalindromesUsingManachersAlgorithm(INPUT_INDEED));
+        assertEquals(EXPECTED_PALINDROME_CIVIC, palindrome.findAllPalindromesUsingManachersAlgorithm(INPUT_CIVIC));
+        assertEquals(EXPECTED_PALINDROME_ABABAC, palindrome.findAllPalindromesUsingManachersAlgorithm(INPUT_ABABAC));
+    }
+
+    @Test
+    public void whenUsingCenterApproach_thenFindsAllPalindromes() {
+        assertEquals(EXPECTED_PALINDROME_BUBBLE, palindrome.findAllPalindromesUsingCenter(INPUT_BUBBLE));
+        assertEquals(EXPECTED_PALINDROME_INDEED, palindrome.findAllPalindromesUsingCenter(INPUT_INDEED));
+        assertEquals(EXPECTED_PALINDROME_CIVIC, palindrome.findAllPalindromesUsingCenter(INPUT_CIVIC));
+        assertEquals(EXPECTED_PALINDROME_ABABAC, palindrome.findAllPalindromesUsingCenter(INPUT_ABABAC));
+    }
+
+    @Test
+    public void whenUsingBruteForceApproach_thenFindsAllPalindromes() {
+        assertEquals(EXPECTED_PALINDROME_BUBBLE, palindrome.findAllPalindromesUsingBruteForceApproach(INPUT_BUBBLE));
+        assertEquals(EXPECTED_PALINDROME_INDEED, palindrome.findAllPalindromesUsingBruteForceApproach(INPUT_INDEED));
+        assertEquals(EXPECTED_PALINDROME_CIVIC, palindrome.findAllPalindromesUsingBruteForceApproach(INPUT_CIVIC));
+        assertEquals(EXPECTED_PALINDROME_ABABAC, palindrome.findAllPalindromesUsingBruteForceApproach(INPUT_ABABAC));
+    }
+}

algorithms-miscellaneous-1/src/test/java/com/baeldung/algorithms/support/MayFailRule.java

@@ -0,0 +1,38 @@
+package com.baeldung.algorithms.support;
+
+import org.junit.Rule;
+import org.junit.rules.TestRule;
+import org.junit.runner.Description;
+import org.junit.runners.model.Statement;
+
+/**
+ * JUnit custom rule for managing tests that may fail due to heuristics or
+ * randomness. In order to use this, just instantiate this object as a public
+ * field inside the test class and annotate it with {@link Rule}.
+ * 
+ * @author Donato Rimenti
+ *
+ */
+public class MayFailRule implements TestRule {
+
+	/*
+	 * (non-Javadoc)
+	 * 
+	 * @see org.junit.rules.TestRule#apply(org.junit.runners.model.Statement,
+	 * org.junit.runner.Description)
+	 */
+	@Override
+	public Statement apply(Statement base, Description description) {
+		return new Statement() {
+			@Override
+			public void evaluate() throws Throwable {
+				try {
+					base.evaluate();
+				} catch (Throwable e) {
+					// Ignore the exception since we expect this.
+				}
+			}
+		};
+	}
+
+}

algorithms-miscellaneous-2/.gitignore

@@ -0,0 +1,4 @@
+/target/
+.settings/
+.classpath
+.project

algorithms-miscellaneous-2/README.md

@@ -0,0 +1,19 @@
+## Relevant articles:
+
+- [Dijkstra Algorithm in Java](http://www.baeldung.com/java-dijkstra)
+- [Introduction to Cobertura](http://www.baeldung.com/cobertura)
+- [Test a Linked List for Cyclicity](http://www.baeldung.com/java-linked-list-cyclicity)
+- [Introduction to JGraphT](http://www.baeldung.com/jgrapht)
+- [A Maze Solver in Java](http://www.baeldung.com/java-solve-maze)
+- [Create a Sudoku Solver in Java](http://www.baeldung.com/java-sudoku)
+- [Displaying Money Amounts in Words](http://www.baeldung.com/java-money-into-words)
+- [A Collaborative Filtering Recommendation System in Java](http://www.baeldung.com/java-collaborative-filtering-recommendations)
+- [Check If Two Rectangles Overlap In Java](https://www.baeldung.com/java-check-if-two-rectangles-overlap)
+- [Calculate the Distance Between Two Points in Java](https://www.baeldung.com/java-distance-between-two-points)
+- [Find the Intersection of Two Lines in Java](https://www.baeldung.com/java-intersection-of-two-lines)
+- [Round Up to the Nearest Hundred](https://www.baeldung.com/java-round-up-nearest-hundred)
+- [Calculate Percentage in Java](https://www.baeldung.com/java-calculate-percentage)
+- [Converting Between Byte Arrays and Hexadecimal Strings in Java](https://www.baeldung.com/java-byte-arrays-hex-strings)
+- [Convert Latitude and Longitude to a 2D Point in Java](https://www.baeldung.com/java-convert-latitude-longitude)
+- [Reversing a Binary Tree in Java](https://www.baeldung.com/java-reversing-a-binary-tree)
+- [Find If Two Numbers Are Relatively Prime in Java](https://www.baeldung.com/java-two-relatively-prime-numbers)

algorithms-miscellaneous-2/pom.xml

@@ -0,0 +1,96 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>algorithms-miscellaneous-2</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <name>algorithms-miscellaneous-2</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-math3</artifactId>
+            <version>${commons-math3.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>commons-codec</groupId>
+            <artifactId>commons-codec</artifactId>
+            <version>${commons-codec.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <version>${lombok.version}</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.jgrapht</groupId>
+            <artifactId>jgrapht-core</artifactId>
+            <version>${org.jgrapht.core.version}</version>
+        </dependency>
+        <dependency>
+        	<groupId>org.jgrapht</groupId>
+        	<artifactId>jgrapht-ext</artifactId>
+        	<version>${org.jgrapht.ext.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>pl.allegro.finance</groupId>
+            <artifactId>tradukisto</artifactId>
+            <version>${tradukisto.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${org.assertj.core.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>org.codehaus.mojo</groupId>
+                    <artifactId>exec-maven-plugin</artifactId>
+                    <version>${exec-maven-plugin.version}</version>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+
+    <reporting>
+        <plugins>
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>cobertura-maven-plugin</artifactId>
+                <version>${cobertura-maven-plugin.version}</version>
+                <configuration>
+                    <instrumentation>
+                        <ignores>
+                            <ignore>com/baeldung/algorithms/dijkstra/*</ignore>
+                        </ignores>
+                        <excludes>
+                            <exclude>com/baeldung/algorithms/dijkstra/*</exclude>
+                        </excludes>
+                    </instrumentation>
+                </configuration>
+            </plugin>
+        </plugins>
+    </reporting>
+
+    <properties>
+        <commons-math3.version>3.6.1</commons-math3.version>
+        <tradukisto.version>1.0.1</tradukisto.version>
+        <org.jgrapht.core.version>1.0.1</org.jgrapht.core.version>
+        <org.jgrapht.ext.version>1.0.1</org.jgrapht.ext.version>
+        <org.assertj.core.version>3.9.0</org.assertj.core.version>
+        <commons-codec.version>1.11</commons-codec.version>
+        <cobertura-maven-plugin.version>2.7</cobertura-maven-plugin.version>
+    </properties>
+
+</project>

algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/RunAlgorithm.java

@@ -0,0 +1,28 @@
+package com.baeldung.algorithms;
+
+import java.util.Scanner;
+
+import com.baeldung.algorithms.slope_one.SlopeOne;
+
+public class RunAlgorithm {
+
+	public static void main(String[] args) throws InstantiationException, IllegalAccessException {
+		Scanner in = new Scanner(System.in);
+		System.out.println("1 - Slope One");
+		System.out.println("2 - Dijkstra");
+		int decision = in.nextInt();
+		switch (decision) {
+		case 1:
+			SlopeOne.slopeOne(3);
+			break;
+		case 2:
+			System.out.println("Please run the DijkstraAlgorithmLongRunningUnitTest.");
+			break;
+		default:
+			System.out.println("Unknown option");
+			break;
+		}
+		in.close();
+	}
+
+}

algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/conversion/HexStringConverter.java

@@ -0,0 +1,110 @@
+package com.baeldung.algorithms.conversion;
+
+import java.math.BigInteger;
+
+import javax.xml.bind.DatatypeConverter;
+
+import org.apache.commons.codec.DecoderException;
+import org.apache.commons.codec.binary.Hex;
+
+import com.google.common.io.BaseEncoding;
+
+public class HexStringConverter {
+
+    /**
+     * Create a byte Array from String of hexadecimal digits using Character conversion 
+     * @param hexString - Hexadecimal digits as String
+     * @return Desired byte Array
+     */
+    public byte[] decodeHexString(String hexString) {
+        if (hexString.length() % 2 == 1) {
+            throw new IllegalArgumentException("Invalid hexadecimal String supplied.");
+        }
+        byte[] bytes = new byte[hexString.length() / 2];
+
+        for (int i = 0; i < hexString.length(); i += 2) {
+            bytes[i / 2] = hexToByte(hexString.substring(i, i + 2));
+        }
+        return bytes;
+    }
+
+    /**
+     * Create a String of hexadecimal digits from a byte Array using Character conversion
+     * @param byteArray - The byte Array
+     * @return Desired String of hexadecimal digits in lower case
+     */
+    public String encodeHexString(byte[] byteArray) {
+        StringBuffer hexStringBuffer = new StringBuffer();
+        for (int i = 0; i < byteArray.length; i++) {
+            hexStringBuffer.append(byteToHex(byteArray[i]));
+        }
+        return hexStringBuffer.toString();
+    }
+
+    public String byteToHex(byte num) {
+        char[] hexDigits = new char[2];
+        hexDigits[0] = Character.forDigit((num >> 4) & 0xF, 16);
+        hexDigits[1] = Character.forDigit((num & 0xF), 16);
+        return new String(hexDigits);
+    }
+
+    public byte hexToByte(String hexString) {
+        int firstDigit = toDigit(hexString.charAt(0));
+        int secondDigit = toDigit(hexString.charAt(1));
+        return (byte) ((firstDigit << 4) + secondDigit);
+    }
+
+    private int toDigit(char hexChar) {
+        int digit = Character.digit(hexChar, 16);
+        if(digit == -1) {
+            throw new IllegalArgumentException("Invalid Hexadecimal Character: "+ hexChar);
+        }
+        return digit;
+    }
+
+    public String encodeUsingBigIntegerToString(byte[] bytes) {
+        BigInteger bigInteger = new BigInteger(1, bytes);
+        return bigInteger.toString(16);
+    }
+
+    public String encodeUsingBigIntegerStringFormat(byte[] bytes) {
+        BigInteger bigInteger = new BigInteger(1, bytes);
+        return String.format("%0" + (bytes.length << 1) + "x", bigInteger);
+    }
+
+    public byte[] decodeUsingBigInteger(String hexString) {
+        byte[] byteArray = new BigInteger(hexString, 16).toByteArray();
+        if (byteArray[0] == 0) {
+            byte[] output = new byte[byteArray.length - 1];
+            System.arraycopy(byteArray, 1, output, 0, output.length);
+            return output;
+        }
+        return byteArray;
+    }
+
+    public String encodeUsingDataTypeConverter(byte[] bytes) {
+        return DatatypeConverter.printHexBinary(bytes);
+    }
+
+    public byte[] decodeUsingDataTypeConverter(String hexString) {
+        return DatatypeConverter.parseHexBinary(hexString);
+    }
+
+    public String encodeUsingApacheCommons(byte[] bytes) throws DecoderException {
+        return Hex.encodeHexString(bytes);
+    }
+
+    public byte[] decodeUsingApacheCommons(String hexString) throws DecoderException {
+        return Hex.decodeHex(hexString);
+    }
+
+    public String encodeUsingGuava(byte[] bytes) {
+        return BaseEncoding.base16()
+            .encode(bytes);
+    }
+
+    public byte[] decodeUsingGuava(String hexString) {
+        return BaseEncoding.base16()
+            .decode(hexString.toUpperCase());
+    }
+}

algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/editdistance/EditDistanceBase.java

@@ -0,0 +1,15 @@
+package com.baeldung.algorithms.editdistance;
+
+import java.util.Arrays;
+
+public class EditDistanceBase {
+
+    static int costOfSubstitution(char a, char b) {
+        return a == b ? 0 : 1;
+    }
+
+    static int min(int... numbers) {
+        return Arrays.stream(numbers)
+          .min().orElse(Integer.MAX_VALUE);
+    }
+}

algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/editdistance/EditDistanceDynamicProgramming.java

@@ -0,0 +1,26 @@
+package com.baeldung.algorithms.editdistance;
+
+public class EditDistanceDynamicProgramming extends EditDistanceBase {
+
+    static int calculate(String x, String y) {
+        int[][] dp = new int[x.length() + 1][y.length() + 1];
+
+        for (int i = 0; i <= x.length(); i++) {
+            for (int j = 0; j <= y.length(); j++) {
+                if (i == 0)
+                    dp[i][j] = j;
+
+                else if (j == 0)
+                    dp[i][j] = i;
+
+                else {
+                    dp[i][j] = min(dp[i - 1][j - 1]
+                        + costOfSubstitution(x.charAt(i - 1), y.charAt(j - 1)),
+                      dp[i - 1][j] + 1, dp[i][j - 1] + 1);
+                }
+            }
+        }
+
+        return dp[x.length()][y.length()];
+    }
+}

algorithms-miscellaneous-2/src/main/java/com/baeldung/algorithms/editdistance/EditDistanceRecursive.java

@@ -0,0 +1,21 @@
+package com.baeldung.algorithms.editdistance;
+
+public class EditDistanceRecursive extends EditDistanceBase {
+
+    static int calculate(String x, String y) {
+
+        if (x.isEmpty()) {
+            return y.length();
+        }
+
+        if (y.isEmpty()) {
+            return x.length();
+        }
+
+        int substitution = calculate(x.substring(1), y.substring(1)) + costOfSubstitution(x.charAt(0), y.charAt(0));
+        int insertion = calculate(x, y.substring(1)) + 1;
+        int deletion = calculate(x.substring(1), y) + 1;
+
+        return min(substitution, insertion, deletion);
+    }
+}