【js基础】js排序方法——快排+堆排+插排+选择排

快排

　　　　　　　　Array.prototype.fastSort = function(){
                 var arr = this;

                 function sort(left, right, arr){
                     if( left >= right){
                         return;
                     }
                     var key = arr[left];
                     var i = left;
                     var j = right;
                     
                     while(i < j){
                         while(i < j && arr[j] >= key){
                             j--;
                         }
                         arr[i] = arr[j];
                         while(i < j && arr[i] <= key){
                             i++;
                         }
                         arr[j] = arr[i];
                     }
                     arr[i] = key;
                     sort(left, i - 1, arr);
                     sort(i + 1, right, arr);
                 }

                 sort(0, arr.length - 1, arr);

                 return arr;
             }

插排

　　　　　　　　Array.prototype.insertSort = function(){
                 var arr = this;
                 var len = arr.length;
                 for(var i = 1; i < len; i ++ ){
                     var j = i - 1;
                     var tmp = arr[i];
                     while(j >= 0 && tmp < arr[j]){
                         arr[j + 1] = arr[j];
                         j--;
                     }
                     if(j != i - 1){
                         arr[j + 1] = tmp;
                     }
                 }
                 return arr;
             }

选择排序

　　　　　　　　Array.prototype.selectSort = function(){
                 var arr = this;
                 var len = arr.length;
                 var min;
                 var tmp;
                 for(var i = 0; i < len - 1; i ++ ){
                     min = i;
                     for(var j = i + 1; j < len; j++){
                         if(arr[min] > arr[j]){
                             min = j;
                         }
                     }
                     if(min != i){
                         tmp = arr[min];
                         arr[min] = arr[i];
                         arr[i] = tmp;
                     }
                 }
                 return arr;
             }

堆排序

　　　　　　　Array.prototype.swap = function(i, j){
                var tmp = this[i];
                this[i] = this[j];
                this[j] = tmp;
            }

            //大顶堆
            Array.prototype.buildMaxHeap = function(){
                for(var i = Math.floor(this.length/2) - 1; i >= 0; i--){
                    this.heapAdjust(i, this.length);
                }
            };

            //调整堆
            Array.prototype.heapAdjust = function(i, j){
                var max = i;
                var left = 2 * i + 1;
                var right = 2 * i + 2;
                if(left < j && this[max] < this[left]){
                    max = left;
                }                 
                if(right < j && this[max] < this[right]){
                    max = right;
                }                 
                if(max != i){
                    this.swap(i,max);
                    this.heapAdjust(max,j);
                };
            }
            
            //堆排序
            Array.prototype.heapSort = function(){
                this.buildMaxHeap();
                for(var i = this.length - 1; i >= 0 ; i--){
                    this.swap(0, i);
                    this.heapAdjust(0, i);
                }
                return this;
            };