text: /**
   * 快速排序
   * @param  {Array}  arr 需要进行快速排序的数组
   * @return {[type]}     [description]
   */
  function quickSort(arr) {
      if (arr.length <= 1) {
          return arr;
      }
  
      var partitionIndex = Math.floor(arr.length / 2),
          temp,
          left = [],
          right = [];
      
      tmp = arr[partitionIndex];
  
      for (var i = 0; i < arr.length; i++) {
  
          if (arr[i] < tmp) {
              left.push(arr[i])
          } else {
              right.push(arr[i])
          }
      }
  
      return quickSort(left).concat([tmp], quickSort(right));
  }