// quick sort

class RecSortExample {

   public static void main (String[] args) {

	int[] list = {15,8,7,3,2,14,11,1,5,9,4,12,13,6,10};

	System.out.println ();

	System.out.println ("Here is the original list of integers ");

	System.out.println ();

	for (int i = 0; i < list.length; i++)
	   System.out.print (list[i] + "  ");
        System.out.println ();
	
	quickSort (list, 0, list.length - 1);

	System.out.println ();
	System.out.println ();

	System.out.println ("Here is the sorted list of integers ");

	System.out.println ();

	for (int i = 0; i < list.length; i++)
	   System.out.print (list[i] + "  ");
        System.out.println ();

	
   }

   static int[] quickSort (int[] list, int low, int high) {

	if (low < high) {

	   int mid = partition (list, low, high);
	   quickSort (list, low, mid - 1);
	   quickSort (list, mid + 1, high);
        }

	return list;
   }

   static int partition (int[] list, int start, int end) {

	// the first number in the list is the pivot

	int pivot = list[start];
	
	do {

	// look for a number smaller than the pivot starting 
	// from the end of the list

	   while (start < end && list[end] >= pivot) {
	     end--;
	   }

	   if (start < end) {  // a smaller number found

	      list[start] = list[end];

	      // now find a number larger than the pivot
	      // from the start

	      while (start < end && list[start] <= pivot) {
	         start++;
	      }

	      if (start < end) {  // a larger number found

		 list[end] = list[start];

	      }
	   }
	} while (start < end);

        // done -- move the pivot back to the array

	list[start] = pivot;

	return start;
    } // end partition
}