Merge pull request #1 from eugenp/master

Update

.gitignore

@@ -64,3 +64,5 @@ jmeter/src/main/resources/*-JMeter.csv
 **/out-tsc
 **/nbproject/
 **/nb-configuration.xml
+core-scala/.cache-main
+core-scala/.cache-tests

.travis.yml

@@ -4,7 +4,7 @@ before_install:
   - echo "MAVEN_OPTS='-Xmx2048M -Xss128M -XX:+CMSClassUnloadingEnabled -XX:+UseG1GC -XX:-UseGCOverheadLimit'" > ~/.mavenrc
 
 install: skip
-script: travis_wait 60 mvn -q install -Pdefault-first,default-second
+script: travis_wait 60 mvn -q install -Pdefault-first,default-second -Dgib.enabled=true
 
 sudo: required
 

JGit/src/main/java/com/baeldung/jgit/porcelain/Log.java

@@ -28,14 +28,14 @@ public class Log {
                 System.out.println("Had " + count + " commits overall on current branch");
 
                 logs = git.log()
-                        .add(repository.resolve("remotes/origin/testbranch"))
+                        .add(repository.resolve(git.getRepository().getFullBranch()))
                         .call();
                 count = 0;
                 for (RevCommit rev : logs) {
                     System.out.println("Commit: " + rev /* + ", name: " + rev.getName() + ", id: " + rev.getId().getName() */);
                     count++;
                 }
-                System.out.println("Had " + count + " commits overall on test-branch");
+                System.out.println("Had " + count + " commits overall on "+git.getRepository().getFullBranch());
 
                 logs = git.log()
                         .all()

JGit/src/test/java/com/baeldung/jgit/JGitBugIntegrationTest.java

@@ -1,3 +1,5 @@
+package com.baeldung.jgit;
+
 import com.baeldung.jgit.helper.Helper;
 import org.eclipse.jgit.lib.ObjectLoader;
 import org.eclipse.jgit.lib.ObjectReader;

akka-http/pom.xml

@@ -0,0 +1,48 @@
+<?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>${akka.http.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>com.typesafe.akka</groupId>
+			<artifactId>akka-stream_2.12</artifactId>
+			<version>2.5.11</version>
+		</dependency>
+		<dependency>
+			<groupId>com.typesafe.akka</groupId>
+			<artifactId>akka-http-jackson_2.12</artifactId>
+			<version>${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>
+		<java.version>1.8</java.version>
+		<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

@@ -0,0 +1,26 @@
+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

@@ -0,0 +1,41 @@
+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

@@ -0,0 +1,49 @@
+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

@@ -0,0 +1,70 @@
+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

@@ -0,0 +1,35 @@
+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

@@ -0,0 +1,50 @@
+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\"}";
+  }
+
+}

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 +1,65 @@
+<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>
+        <lombok.version>1.16.12</lombok.version>
+        <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

@@ -5,7 +5,6 @@ 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;
-import com.baeldung.algorithms.slope_one.SlopeOne;
 
 public class RunAlgorithm {
 
@@ -13,11 +12,8 @@ public class RunAlgorithm {
 		Scanner in = new Scanner(System.in);
 		System.out.println("Run algorithm:");
 		System.out.println("1 - Simulated Annealing");
-		System.out.println("2 - Slope One");
-		System.out.println("3 - Simple Genetic Algorithm");
-		System.out.println("4 - Ant Colony");
-		System.out.println("5 - Dijkstra");
-		System.out.println("6 - All pairs in an array that add up to a given sum");
+		System.out.println("2 - Simple Genetic Algorithm");
+		System.out.println("3 - Ant Colony");
 		int decision = in.nextInt();
 		switch (decision) {
 		case 1:
@@ -25,19 +21,13 @@ public class RunAlgorithm {
 					"Optimized distance for travel: " + SimulatedAnnealing.simulateAnnealing(10, 10000, 0.9995));
 			break;
 		case 2:
-			SlopeOne.slopeOne(3);
-			break;
-		case 3:
 			SimpleGeneticAlgorithm ga = new SimpleGeneticAlgorithm();
 			ga.runAlgorithm(50, "1011000100000100010000100000100111001000000100000100000000001111");
 			break;
-		case 4:
+		case 3:
 			AntColonyOptimization antColony = new AntColonyOptimization(21);
 			antColony.startAntOptimization();
 			break;
-		case 5:
-			System.out.println("Please run the DijkstraAlgorithmTest.");
-			break;
 		default:
 			System.out.println("Unknown option");
 			break;

algorithms-miscellaneous-1/.gitignore

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

algorithms-miscellaneous-1/README.md

@@ -0,0 +1,15 @@
+## 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)

algorithms-miscellaneous-1/pom.xml

@@ -0,0 +1,84 @@
+<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>${org.assertj.core.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>org.codehaus.mojo</groupId>
+                    <artifactId>exec-maven-plugin</artifactId>
+                    <version>${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>
+        <lombok.version>1.16.12</lombok.version>
+        <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>25.1-jre</guava.version>
+    </properties>
+
+</project>

algorithms-miscellaneous-1/src/main/java/com/baeldung/algorithms/factorial/Factorial.java

@@ -0,0 +1,63 @@
+package com.baeldung.algorithms.factorial;
+
+import java.math.BigInteger;
+import java.util.stream.LongStream;
+
+import org.apache.commons.math3.util.CombinatoricsUtils;
+
+import com.google.common.math.BigIntegerMath;
+
+public class Factorial {
+
+    public long factorialUsingForLoop(int n) {
+        long fact = 1;
+        for (int i = 2; i <= n; i++) {
+            fact = fact * i;
+        }
+        return fact;
+    }
+
+    public long factorialUsingStreams(int n) {
+        return LongStream.rangeClosed(1, n)
+            .reduce(1, (long x, long y) -> x * y);
+    }
+
+    public long factorialUsingRecursion(int n) {
+        if (n <= 2) {
+            return n;
+        }
+        return n * factorialUsingRecursion(n - 1);
+    }
+
+    private Long[] factorials = new Long[20];
+
+    public long factorialUsingMemoize(int n) {
+
+        if (factorials[n] != null) {
+            return factorials[n];
+        }
+
+        if (n <= 2) {
+            return n;
+        }
+        long nthValue = n * factorialUsingMemoize(n - 1);
+        factorials[n] = nthValue;
+        return nthValue;
+    }
+
+    public BigInteger factorialHavingLargeResult(int n) {
+        BigInteger result = BigInteger.ONE;
+        for (int i = 2; i <= n; i++)
+            result = result.multiply(BigInteger.valueOf(i));
+        return result;
+    }
+
+    public long factorialUsingApacheCommons(int n) {
+        return CombinatoricsUtils.factorial(n);
+    }
+
+    public BigInteger factorialUsingGuava(int n) {
+        return BigIntegerMath.factorial(n);
+    }
+
+}

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/test/java/com/baeldung/algorithms/factorial/FactorialUnitTest.java

@@ -0,0 +1,72 @@
+package com.baeldung.algorithms.factorial;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.math.BigInteger;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class FactorialUnitTest {
+
+    Factorial factorial;
+
+    @Before
+    public void setup() {
+        factorial = new Factorial();
+    }
+
+    @Test
+    public void whenCalculatingFactorialUsingForLoop_thenCorrect() {
+        int n = 5;
+
+        assertThat(factorial.factorialUsingForLoop(n)).isEqualTo(120);
+    }
+
+    @Test
+    public void whenCalculatingFactorialUsingStreams_thenCorrect() {
+        int n = 5;
+
+        assertThat(factorial.factorialUsingStreams(n)).isEqualTo(120);
+    }
+
+    @Test
+    public void whenCalculatingFactorialUsingRecursion_thenCorrect() {
+        int n = 5;
+
+        assertThat(factorial.factorialUsingRecursion(n)).isEqualTo(120);
+    }
+
+    @Test
+    public void whenCalculatingFactorialUsingMemoize_thenCorrect() {
+        int n = 5;
+
+        assertThat(factorial.factorialUsingMemoize(n)).isEqualTo(120);
+
+        n = 6;
+
+        assertThat(factorial.factorialUsingMemoize(n)).isEqualTo(720);
+    }
+
+    @Test
+    public void whenCalculatingFactorialHavingLargeResult_thenCorrect() {
+        int n = 22;
+
+        assertThat(factorial.factorialHavingLargeResult(n)).isEqualTo(new BigInteger("1124000727777607680000"));
+    }
+
+    @Test
+    public void whenCalculatingFactorialUsingApacheCommons_thenCorrect() {
+        int n = 5;
+
+        assertThat(factorial.factorialUsingApacheCommons(n)).isEqualTo(120);
+    }
+
+    @Test
+    public void whenCalculatingFactorialUsingGuava_thenCorrect() {
+        int n = 22;
+
+        assertThat(factorial.factorialUsingGuava(n)).isEqualTo(new BigInteger("1124000727777607680000"));
+    }
+
+}

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-2/.gitignore

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

algorithms-miscellaneous-2/README.md

@@ -2,35 +2,19 @@
 
 - [Dijkstra Algorithm in Java](http://www.baeldung.com/java-dijkstra)
 - [Introduction to Cobertura](http://www.baeldung.com/cobertura)
-- [Ant Colony Optimization](http://www.baeldung.com/java-ant-colony-optimization)
-- [Validating Input With Finite Automata in Java](http://www.baeldung.com/java-finite-automata)
-- [Introduction to Jenetics Library](http://www.baeldung.com/jenetics)
-- [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)
-- [String Search Algorithms for Large Texts](http://www.baeldung.com/java-full-text-search-algorithms)
 - [Test a Linked List for Cyclicity](http://www.baeldung.com/java-linked-list-cyclicity)
-- [Binary Search Algorithm in Java](http://www.baeldung.com/java-binary-search)
-- [Bubble Sort in Java](http://www.baeldung.com/java-bubble-sort)
 - [Introduction to JGraphT](http://www.baeldung.com/jgrapht)
-- [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)
 - [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)
 - [Converting Between Roman and Arabic Numerals in Java](http://www.baeldung.com/java-convert-roman-arabic)
 - [Practical Java Examples of the Big O Notation](http://www.baeldung.com/java-algorithm-complexity)
-- [Find the Middle Element of a Linked List](http://www.baeldung.com/java-linked-list-middle-element)
 - [An Introduction to the Theory of Big-O Notation](http://www.baeldung.com/big-o-notation)
 - [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)
-- [Check If a String Contains All The Letters of The Alphabet](https://www.baeldung.com/java-string-contains-all-letters)
 - [Round Up to the Nearest Hundred](https://www.baeldung.com/java-round-up-nearest-hundred)
-- [Merge Sort in Java](https://www.baeldung.com/java-merge-sort)
 - [Calculate Percentage in Java](https://www.baeldung.com/java-calculate-percentage)
-- [Quicksort Algorithm Implementation in Java](https://www.baeldung.com/java-quicksort)
-- [Insertion Sort in Java](https://www.baeldung.com/java-insertion-sort)
 - [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)

algorithms-miscellaneous-2/pom.xml

@@ -1,9 +1,9 @@
 <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>
-    <groupId>com.baeldung</groupId>
-    <artifactId>algorithms</artifactId>
+    <artifactId>algorithms-miscellaneous-2</artifactId>
     <version>0.0.1-SNAPSHOT</version>
+    <name>algorithms-miscellaneous-2</name>
 
     <parent>
         <groupId>com.baeldung</groupId>
@@ -28,16 +28,16 @@
             <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.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>
@@ -87,8 +87,8 @@
         <lombok.version>1.16.12</lombok.version>
         <commons-math3.version>3.6.1</commons-math3.version>
         <tradukisto.version>1.0.1</tradukisto.version>
-        <io.jenetics.version>3.7.0</io.jenetics.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>
     </properties>

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();
+	}
+
+}