Quick Sort Algorithm in Java Programming

Quick Sort Algorithm

Quick Sort Algorithm example in Java Programming :

public class QuickSort {

  public static void main(String a[]) {

    int i;
    int array[] = { 12, 9, 4, 99, 120, 1, 3, 10, 13 };

    System.out.println("Quick Sort\n\n");
    System.out.println("Values Before the sort:\n");

    for (i = 0; i < array.length; i++) {

      System.out.print(array[i] + "  ");

    }

    System.out.println();

    quick_srt(array, 0, array.length - 1);

    System.out.print("\nValues after the sort:\n\n");

    for (i = 0; i < array.length; i++) {

      System.out.print(array[i] + "  ");

    }

    System.out.println();
  }

  public static void quick_srt(int array[], int low, int n) {

    int lo = low;
    int hi = n;

    if (lo >= n) {

      return;

    }

    int mid = array[(lo + hi) / 2];

    while (lo < hi) {

      while (lo < hi && array[lo] < mid) {

        lo++;

      }

      while (lo < hi && array[hi] > mid) {

        hi--;

      }

      if (lo < hi) {

        int T = array[lo];
        array[lo] = array[hi];
        array[hi] = T;

      }
    }

    if (hi < lo) {

      int T = hi;
      hi = lo;
      lo = T;

    }

    quick_srt(array, low, lo);
    quick_srt(array, lo == low ? lo + 1 : lo, n);

  }
}

OUTPUT

Quick Sort
Values Before the sort:
12  9  4  99  120  1  3  10  13 
Values after the sort:
1  3  4  9  10  12  13  99  120