JS实现排序算法

代码如下：

1、冒泡排序

 1 <script>
 2     var arr = [9, 8, 7, 5, 7, 1, 45, 12, 7, 74, 4];
 3     for (var i = 0; i < arr.length; i++) {
 4         for (var j = 0; j < arr.length - i - 1; j++) {
 5             if (arr[j] > arr[j + 1]) {
 6                 var temp=arr[j];
 7                 arr[j]=arr[j+1];
 8                 arr[j+1]=temp;
 9             }
10         }
11     }
12     console.log(arr);
13 </script>

2、选择排序

 1 <script>
 2     var arr = [9, 8, 7, 5, 7, 1, 45, 12, 7, 74, 4];
 3     for (var i = 0; i < arr.length - 1; i++) {
 4         for (var j = i + 1; j < arr.length; j++) {
 5             if (arr[i] > arr[j]) {
 6                 var temp = arr[j];
 7                 arr[j] = arr[i];
 8                 arr[i] = temp;
 9             }
10         }
11     }
12     console.log(arr);
13 </script>

3、快速排序

 1 <script>
 2     var arr = [9, 8, 7, 5, 7, 1, 45, 12, 7, 74, 4];
 3 
 4     function quickSort(arr) {
 5         // 递归停止条件
 6         if (arr.length <= 1) {
 7             return arr;
 8         }
 9         var midIndex = parseInt(arr.length / 2);
10         var left = [];
11         var right = [];
12         arr.forEach(function (item, index) {
13             if (index == midIndex) {
14 
15             } else if (arr[index] < arr[midIndex]) {
16                 left.push(arr[index]);
17             } else {
18                 right.push(arr[index]);
19             }
20         });
21         return quickSort(left).concat(arr[midIndex]).concat(quickSort(right));
22     }
23     console.log(quickSort(arr));
24 </script>

4、插入排序

<script>
    var arr = [9, 8, 7, 5, 7, 1, 45, 12, 7, 74, 4];

    for (var i = 0; i < arr.length; i++) {
        var m=i;
        while (i - 1 >= 0 && arr[m] < arr[m - 1]) {
            var temp=arr[m];
            arr[m]=arr[m-1];
            arr[m-1]=temp;
            m--;
        }
    }
    console.log(arr);
</script>

5、希尔排序

 1 <script>
 2     var arr = [9, 8, 7, 5, 7, 1, 45, 12, 7, 74, 4];
 3     //设定步长初始值
 4     var interval = parseInt(arr.length / 2);
 5     while (interval > 0) {
 6         for (var i = 0; i < arr.length; i++) {
 7             var m = i;
 8             while (i - 1 >= 0 && arr[m] < arr[m - interval]) {
 9                 var temp = arr[m];
10                 arr[m] = arr[m - interval];
11                 arr[m - interval] = temp;
12                 m--;
13             }
14         }
15         interval = parseInt(interval / 2);
16     }
17     console.log(arr);
18 </script>