Quick Sort

Source:

import java.io.*;
import java.util.*;
 
public class QuickSort {
   public static void swap (int A[], int x, int y) {
      int temp = A[x];
      A[x] = A[y];
      A[y] = temp;
   }
 
   public static int partition(int A[], int f, int l) {
      int pivot = A[f];
      while (f < l) {
         while (A[f] < pivot) f++;
         while (A[l] > pivot) l--;
         swap (A, f, l);
      }
      return f;
   }
 
   public static void Quicksort(int A[], int f, int l) {
      if (f >= l) return;
      int pivot_index = partition(A, f, l);
      Quicksort(A, f, pivot_index);
      Quicksort(A, pivot_index+1, l);
   }
 
   public static void main(String argv[]) {
      int []numbers={55,2,93,1,23,10,66,12,7,54,3};
      System.out.println(Arrays.toString(numbers));
      Quicksort(numbers, 0, numbers.length-1);
      System.out.println(Arrays.toString(numbers));
   }
}

Output:

   $ java QuickSort 
   [55, 2, 93, 1, 23, 10, 66, 12, 7, 54, 3]
   [1, 2, 3, 7, 10, 12, 23, 54, 55, 66, 93]