快速排序算法

 // 快速排序算法
    // 时间复杂度为 O(n logn)
    function quickSort(arr) {
      if(arr.length < 2){ return arr };
      var pivotIndex = Math.floor(arr.length / 2);
      var pivot = arr.splice(pivotIndex, 1)[0];
      var left = [];
      var right = [];
      for(var i = 0; i < arr.length; i++){
        if(arr[i] <= pivot){
          left.push(arr[i]);
        }else{
          right.push(arr[i]);
        }
      }
      return quickSort(left).concat([pivot], quickSort(right));
    }

    function getRandomNumbers(min, max, count) {
      count = count || 10;
      min = min || 0;
      max = max || 10;
      var res = [];
      var temp;
      var cap = max - min;
      for (var i = 0; i < count; i++) {
        temp = Number((Math.random() * cap + min).toFixed(2));
        res.push(temp)
      }
      return res;
    }
    console.time()
    console.log(quickSort(getRandomNumbers(1, 30, 10)))
    console.timeEnd()