用JS实现的常见几种排序算法

1.快速排序法

function quickSort(a) {

                if (a.length <= 1) {

                        return a;

                }

                var midLength = Math.floor(a.length / 2);

                var midValue = a.splice(midLength,1);

                var left = [];

                var right = [];

                for (var i = 0; i < a.length; i++) {

                        if (a[i] < midValue) {

                                left.push(a[i]);

                        } else {

                                right.push(a[i]);

                        }

                }

                return quickSort(left).concat(midValue,quickSort(right));

        }

        console.log(quickSort([1,5,3,6,2,4,0]));

 

2.插入排序法

function insertSort(a) {

                var length = a.length;

                var sortArray;

                for (var i = 1; i < length; i++) {

                        for (var j = 0; j < i ; j++) {

                                if (a[i] < a[j]) {

                                        sortArray = a[i];

                                        a[i] = a[j];

                                        a[j] = sortArray;

                                }

                        }

                }

                return a;

        }

        console.log(insertSort([0,6,5,3,4,2,1,7]));

 

3.冒泡排序

function bubbleSort(a) {

                var length = a.length;

                var sortArray;

                for (var i = 0; i < length-1; i++) {

                        for (var j = 0; j < length-i-1 ; j++) {

                                if (a[j] > a[j+1]) {

                                        sortArray = a[j];

                                        a[j] = a[j+1];

                                        a[j+1] = sortArray;

                                }

                        }

                }

                return a;

        }

        console.log(bubbleSort([2,1,3,6,5,4,7,0]));

 

4.选择排序

 function selectSort(a) {

                for (var i = 0; i < a.length; i++) {

                        var min = a[i];

                        var k = i;

                        for (var j = i + 1; j < a.length; j++) {

                                if (min > a[j]) {

                                        min = a[j];

                                        k = j;

                                }

                        }

                        a[k] = a[i];

                        a[i] = min;

                }

                return a;

        }

        console.log(selectSort([5,1,4,0,3,2,7,6]));