1  public class QuickSort {
  2    public static void quickSort(int[] list) {
  3      quickSort(list, 0, list.length - 1);
  4    }
  5  
  6    private static void quickSort(int[] list, int first, int last) {
  7      if (last > first) {
  8        int pivotIndex = partition(list, first, last);
  9        quickSort(list, first, pivotIndex - 1);
 10        quickSort(list, pivotIndex + 1, last);
 11      }
 12    }
 13  
 14    /** Partition the array list[first..last] */
 15    private static int partition(int[] list, int first, int last) {
 16      int pivot = list[first]; // Choose the first element as the pivot
 17      int low = first + 1; // Index for forward search
 18      int high = last; // Index for backward search
 19  
 20      while (high > low) {
 21        // Search forward from left
 22        while (low <= high && list[low] <= pivot)
 23          low++;
 24  
 25        // Search backward from right
 26        while (low <= high && list[high] > pivot)
 27          high--;
 28  
 29        // Swap two elements in the list
 30        if (high > low) {
 31          int temp = list[high];
 32          list[high] = list[low];
 33          list[low] = temp;
 34        }
 35      }
 36  
 37      while (high > first && list[high] >= pivot)
 38        high--;
 39  
 40      // Swap pivot with list[high]
 41      if (pivot > list[high]) {
 42        list[first] = list[high];
 43        list[high] = pivot;
 44        return high;
 45      }
 46      else {
 47        return first;
 48      }
 49    }
 50  
 51    /** A test method */
 52    public static void main(String[] args) {
 53      int[] list = {2, 3, 2, 5, 6, 1, -2, 3, 14, 12};
 54      quickSort(list);
 55      for (int i = 0; i < list.length; i++)
 56        System.out.print(list[i] + " ");
 57    }
 58  }