import java.util.Scanner;

public class QuickSort {
    public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter the number of elements : ");
        int n = sc.nextInt();
        int arr[] = new int[n];
        System.out.println("Enter " + n + " elements :");
        for (int i = 0; i < n; i++)
            arr[i] = sc.nextInt();

        quickSort(arr, 0, n - 1);

        System.out.println("\nThe sorted array : ;");
        for (int i = 0; i < n; i++)
            System.out.print(arr[i] + " ");
        System.out.println();
    }

    /**
     * @param arr   The array/sub-array to be sorted
     * @param lower lower index
     * @param upper upper index
     */
    static void quickSort(int arr[], int lower, int upper) {
        if (lower >= upper)
            return;
        int p = partition(arr, lower, upper);
        quickSort(arr, lower, p - 1);
        quickSort(arr, p + 1, upper);
    }

    /**
     * @param arr   The array of elements
     * @param lower The lower index of the elements
     * @param upper The upper index of the elements
     * @return The index of the pivot element
     */
    private static int partition(int arr[], int lower, int upper) {
        int pivot = arr[upper];
        int j = lower;
        int tmp;
        for (int i = lower; i <= upper; i++) {
            if (arr[i] < pivot) {
                tmp = arr[i];
                arr[i] = arr[j];
                arr[j] = tmp;
                j++;
            }
        }
        tmp = arr[upper];
        arr[upper] = arr[j];
        arr[j] = tmp;

        return j;
    }
}