数组排序

数组排序

1. 快速排序法

   // 快速排序
   var quickSort = function(arr) {
       if(arr.length < 1) {//如果数组就是一项，那么可以直接返回
           return arr;
       }
       var centerIndex = Math.floor(arr.length / 2);//获取数组中间的索引
       var centerValue = arr[centerIndex];//获取数组中间项
       var left = [], right = [];
       for(var i = 0; i < arr.lenght; i++){
           if(arr[i] < centerValue){
               left.push(arr[i]);
           }else{
               right.push(arr[i]);
           }
       }
       return quickSort(left).contanct([centerValue], quickSort(right));//递归调用
   }
   

2. 选择排序法

   // 插入排序
   var insertSort = function(arr) {
       var len = arr.length;
       var preIndex, current;
       for(var i = 1; i < len; i++){
           preIndex = i - 1;
           current = arr[i];
            while(preIndex >= 0 && arr[preIndex] > current){
               arr[preIndex + 1] = arr[preIndex];
               preIndex--;
           }
           arr[preIndex + 1] = current;
       }
       return arr;
   }
   

3. 冒泡排序法

   // 冒泡排序
   var bubbleSort = function(arr) {
       var len = arr.length;
       for(var i = 0; i < len; i++){
           for(var j = 0; i < len - 1 - i; i++){
               if(arr[j] > arr[j+1]) {//相邻元素两两对比
                   var temp = arr[j+1];//元素交换
                   arr[j+1] = arr[j];
                   arr[j] = temp;
               }
           }
       }
       return arr;
   }