数组排序

1.冒泡排序

 Array.prototype.specialSort = function(){
      //冒泡排序
      var len = this.length,
          a = 0;
      for(var i = 0; i < len; i++){
          for(var j =0; j < len-1; j++){
              if(this[j]>this[j+1]){
                  a = this[j];
                  this[j] = this[j+1];
                  this[j+1] = a;
              }
          }
      }
      return this;
  };
  
  var newArr = [2,4,2,1,6].specialSort();
  console.log(newArr); //[1,2,2,4,6]

2.快速排序

  Array.prototype.quickSort = function(){
      var len = this.length;
      if(len <= 1){
          return this;
      }
      
      var pivot = this.shift();  //基准元素
      var left = [];
      var right = [];
      
      for(var i = 0; i < len-1; i++){
          if(this[i] < pivot){   //小于基准元素的放在左边
              left.push(this[i]);
          }else{
              right.push(this[i]);   //大于基准元素的放在右边
          }
      }
      return left.quickSort().concat([pivot], right.quickSort());
  };
  
  var newArr = [2,4,6,1,3].quickSort();  //[1, 2, 3, 4, 6]
  console.log(newArr);