Quick Sort Program in Java

In this tutorial, you will learn how to implement quick sorting in Java. The quick Sort program algorithm is a very  fast sorting algorithm and is one of the common sorting algorithm which is asked in exams.

Source code for Quick Sort Java Program

public class QuickSort {

   public static void main(String args[]) {

     int[] x = {597, 21, 523, 1378, 243, 774, 14, 93, 510};
     System.out.println("Unsorted list: ");
     display(x);
     quickSort(x, 0, x.length-1);
   }

   private static void quickSort(int x[], int lb, int ub) {
     int j=0;

     if (lb>=ub)
       return;

     j = partition(x, lb, ub);
     System.out.println("After partitioning array from index "+(lb+1)+ " to"+(ub+1)+":");

     display(x);
     quickSort(x, lb, j-1);
     quickSort(x, j+1, ub);
   }

   private static int partition(int x[], int lb, int ub)
   {
     int a, down, temp, up;
     a = x[lb];
     up = ub;
     down = lb;

     while (down < up) {

       while(x[down]<=a && down<up)
         down++;

       while(x[up]>a)
         up--;

       if (down < up) {
         temp = x[down];
         x[down] = x[up];
         x[up] = temp;
       }
     }

     x[lb] = x[up];
     x[up] = a;


     return up;
   }

   private static void display(int x[]) {
     for (int i=0; i<x.length; i++)
       System.out.print(x[i] + " ");
     System.out.println("\n");
   }
}

Output of Quick Sort Java Program 

 

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