QuickSort.java

import java.util.Scanner;

public class QuickSort {
    public static void swap(int[] arr, int a, int b) {
        int temp = arr[a];
        arr[a] = arr[b];
        arr[b] = temp;
    }

    public static int partition(int[] arr, int low, int high) {
        int pivot = arr[high];
        int i = low - 1;
        for (int j = low; j < high; j++) {
            if (arr[j] < pivot) {
                i++;
                swap(arr, i, j);
            }
        }
        swap(arr, i + 1, high);
        return i + 1;
    }

    public static void quickSort(int[] arr, int low, int high) {
        if (low < high) {
            int pi = partition(arr, low, high);
            quickSort(arr, low, pi - 1);
            quickSort(arr, pi + 1, high);
        }
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter the size of array: ");
        int size = sc.nextInt();
        int[] arr = new int[size];
        System.out.print("Enter the elements of array with spaces: ");
        for (int i = 0; i < size; i++) {
            arr[i] = sc.nextInt();
        }
        System.out.print("The sorted array is : ");
        quickSort(arr, 0, size - 1);
        for (int i = 0; i < size; i++) {
            System.out.print(arr[i] + " ");
        }
        sc.close();
    }
}