function quickSort(items, left, right) {
  var index;

  if (items.length > 1) {
    index = partition(items, left, right);

    if (left < index - 1) {
      quickSort(items, left, index - 1);
    }

    if (index < right) {
      quickSort(items, index, right);
    }
  }

  return items;
}