code: private void quicksort(short[] a, int[] indexes, int left, int right) {
          if (right <= left)
              return;
          int i = partition(a, indexes, left, right);
          quicksort(a, indexes, left, i - 1);
          quicksort(a, indexes, i + 1, right);
      }
docs: quicksort a[left] to a[right]