QuickSort.java

import java.util.Scanner;
import java.util.Arrays;
public class QuickSort {
    public static void main(String args[]) {
        int i;
        Scanner scan = new Scanner(System.in);
        int size;
        System.out.print("Enter the size:");
        size = scan.nextInt();
        int arr[] = new int[size];
        System.out.println("Enter the elements:");
        for (i = 0; i < size; i++) {
            arr[i] = scan.nextInt();
        }
        sort(arr, 0, size - 1);
        System.out.println("Sorted array: "+Arrays.toString(arr));
    }

    static void sort(int arr[], int start, int end) {
        if (start < end) {
            int pivotIndex = partition(arr, start, end);
            sort(arr, start, pivotIndex - 1);
            sort(arr, pivotIndex, end);
        }
    }

    static int partition(int arr[], int start, int end) {
        int pivot = arr[end];
        int pivotIndex = start;
        int temp;
        for (int i = start; i < end; i++) {
            if (arr[i] < pivot) {
                temp = arr[i];
                arr[i] = arr[pivotIndex];
                arr[pivotIndex] = temp;
                pivotIndex++;
            }
        }
        temp = arr[pivotIndex];
        arr[pivotIndex] = arr[end];
        arr[end] = temp;
        return pivotIndex;
    }
}