JS实现排序算法

代码如下：

1、冒泡排序

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

2、选择排序

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

3、快速排序

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

    function quickSort(arr) {
        // 递归停止条件
        if (arr.length <= 1) {
            return arr;
        }
        var midIndex = parseInt(arr.length / 2);
        var left = [];
        var right = [];
        arr.forEach(function (item, index) {
            if (index == midIndex) {

            } else if (arr[index] < arr[midIndex]) {
                left.push(arr[index]);
            } else {
                right.push(arr[index]);
            }
        });
        return quickSort(left).concat(arr[midIndex]).concat(quickSort(right));
    }
    console.log(quickSort(arr));
</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

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