/** * 🔥🔥 Quick sort implementatioN 🔥🔥 * * The idea of quick sort algorithm is to * split the array and sort both parts simply * by calling the same method. * * @author Eitan Baruch */ import java.util.Random; public class QuickSort { // Recursive method that splits the array // and sort the two parts public static void sort(int[] arr, int start, int end) { // BASE CASE: Nothing to sort - go home. if ((end - start) < 2) { return; } int pivotIndex = partition(arr, start, end); sort(arr, start, pivotIndex); sort(arr, pivotIndex + 1, end); } private static int partition(int[] input, int start, int end) { int i = start; int j = end; int pivot = input[start]; while (i < j) { // NOTE: this is an empty loop, just to // find the index of the first element, // Which is larger than pivot. while(i < j && input[--j] >= pivot); if (i < j) { input[i] = input[j]; } while(i < j && input[++i] <= pivot); if (i < j) { input[j] = input[i]; } } input[j] = pivot; return j; } // Initiate the array, with random numbers. private static int[] initArr() { int arr[] = new int[9]; Random rnd = new Random(); for(int i = 0; i < arr.length; i++) { arr[i] = rnd.nextInt(30); } return arr; } // Simple method to show the array's content public static void show(String m, int[] arr) { System.out.printf( "%s array of %d elements:\n", m, arr.length); for(int i = 0; i < arr.length; i++) { System.out.print(arr[i] + ", "); } System.out.println("<-"); } // Random initiation, SORT and print the // sorted result public static void main(String[] args) { int[] array = initArr(); show("Random", array); System.out.print("\n Call quick sort."); QuickSort.sort(array, 0, array.length); System.out.println(".... finished.\n"); show("Sorted", array); } } // You are welcome to check more // sorting algorithms: // Bubble Sort // Insertion Sort // // Thank you for your visit :-)

Quick Sort Algorithm