quicksort

private void (int[] array, int left, int right) {
      if (left >= right) { 
          return;
      }
      int n = partition(array, left, right);  // 切分
      help(array, left, n - 1);   //将左半部分排序
      help(array, n + 1, right);  //将右半部分排序
  }

  private int partition(int[] array, int left, int right) {
      int v = array[left];
      while (true) {
          while (v > array[left]) {
              left++;
          }
          while (v < array[right]) {
              right--;
          }
          if (left >= right) {
              break;
          }
          int tmp = array[left];
          array[left] = array[right];
          array[right] = tmp;
      }
      return left;
  }