diff --git a/core-java-modules/core-java-collections-5/src/main/java/com/baeldung/collectionssortcomplexity/CollectionsSortTimeComplexityJMH.java b/core-java-modules/core-java-collections-5/src/main/java/com/baeldung/collectionssortcomplexity/CollectionsSortTimeComplexityJMH.java new file mode 100644 index 0000000000..766a89f674 --- /dev/null +++ b/core-java-modules/core-java-collections-5/src/main/java/com/baeldung/collectionssortcomplexity/CollectionsSortTimeComplexityJMH.java @@ -0,0 +1,60 @@ +package com.baeldung.collectionssortcomplexity; + +import org.openjdk.jmh.annotations.*; + +import java.util.ArrayList; +import java.util.Collections; +import java.util.List; +import java.util.concurrent.TimeUnit; + +@BenchmarkMode(Mode.AverageTime) +@OutputTimeUnit(TimeUnit.MILLISECONDS) +@Fork(value = 1, warmups = 1) +@Warmup(iterations = 5, time = 1) +@Measurement(iterations = 5, time = 1) +public class CollectionsSortTimeComplexityJMH { + + public static void main(String[] args) throws Exception { + org.openjdk.jmh.Main.main(args); + + } + + @Benchmark + public void measureCollectionsSortBestCase(BestCaseBenchmarkState state) { + List sortedList = new ArrayList<>(state.sortedList); + Collections.sort(sortedList); + } + + @Benchmark + public void measureCollectionsSortAverageWorstCase(AverageWorstCaseBenchmarkState state) { + List unsortedList = new ArrayList<>(state.unsortedList); + Collections.sort(unsortedList); + } + + @State(Scope.Benchmark) + public static class BestCaseBenchmarkState { + List sortedList; + + @Setup(Level.Trial) + public void setUp() { + sortedList = new ArrayList<>(); + for (int i = 1; i <= 1000000; i++) { + sortedList.add(i); + } + } + } + + @State(Scope.Benchmark) + public static class AverageWorstCaseBenchmarkState { + List unsortedList; + + @Setup(Level.Trial) + public void setUp() { + unsortedList = new ArrayList<>(); + for (int i = 1000000; i > 0; i--) { + unsortedList.add(i); + } + } + } + +} \ No newline at end of file diff --git a/core-java-modules/core-java-collections-5/src/main/java/com/baeldung/collectionssortcomplexity/CollectionsSortTimeComplexityMain.java b/core-java-modules/core-java-collections-5/src/main/java/com/baeldung/collectionssortcomplexity/CollectionsSortTimeComplexityMain.java new file mode 100644 index 0000000000..f273d3562a --- /dev/null +++ b/core-java-modules/core-java-collections-5/src/main/java/com/baeldung/collectionssortcomplexity/CollectionsSortTimeComplexityMain.java @@ -0,0 +1,33 @@ +package com.baeldung.collectionssortcomplexity; + +import java.util.Arrays; +import java.util.Collections; +import java.util.List; + +public class CollectionsSortTimeComplexityMain { + // O(n log n) Time Complexity Example + public static void worstAndAverageCasesTimeComplexity() { + Integer[] sortedArray = {20, 21, 22, 23, 24, 25, 26, 17, 28, 29, 30, 31, 18, 19, 32, 33, 34, 27, 35}; + List list = Arrays.asList(sortedArray); + Collections.shuffle(list); + long startTime = System.nanoTime(); + Collections.sort(list); + long endTime = System.nanoTime(); + System.out.println("Execution Time for O(n log n): " + (endTime - startTime) + " nanoseconds"); + } + + // O(n) Time Complexity Example + public static void bestCaseTimeComplexity() { + Integer[] sortedArray = {19, 22, 19, 22, 24, 25, 17, 11, 22, 23, 28, 23, 0, 1, 12, 9, 13, 27, 15}; + List list = Arrays.asList(sortedArray); + long startTime = System.nanoTime(); + Collections.sort(list); + long endTime = System.nanoTime(); + System.out.println("Execution Time for O(n): " + (endTime - startTime) + " nanoseconds"); + } + + public static void main(String[] args) { + worstAndAverageCasesTimeComplexity(); + bestCaseTimeComplexity(); + } +}