冒泡排序
function bubbleSort(arr) {
var len = arr.length;
for (var i = 0; i < len; i++) {
for (var j = 0; j < len - 1 - i; j++) {
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;
}
选择排序(在剩下未排序的里面找最小的)
function selectionSort(arr) {
var len = arr.length;
var minIndex, temp;
for (var i = 0; i < len - 1; i++) {
minIndex = i;
for (var j = i + 1; j < len; j++) {
if (arr[j] < arr[minIndex]) { //寻找最小的数
minIndex = j; //将最小数的索引保存
}
}
temp = arr[i];
arr[i] = arr[minIndex];
arr[minIndex] = temp;
}
return arr;
}
插入排序
function insertionSort(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;
}
归并排序
function mergeSort(arr) {
const len = arr.length;
if (len < 2) { return arr; }
const mid = Math.floor(len / 2);
const left = arr.slice(0, mid);
const right = arr.slice(mid);
return merge(mergeSort(left), mergeSort(right));
}
function merge(left, right) {
const result = [];
while (left.length > 0 && right.length > 0) {
result.push(left[0] <= right[0] ? left.shift() : right.shift());
}
return result.concat(left, right);
}
快速排序（基准思想）
function quickSort(arr) {
const pivot = arr[0];
const left = [];
const right = [];
if (arr.length < 2) { return arr; }
for (let i = 1, len = arr.length; i < len; i++) {
arr[i] < pivot ? left.push(arr[i]) : right.push(arr[i]);
}
return quickSort(left).concat([pivot], quickSort(right));
}
计数排序
function countingSort(arr, maxValue) {
var bucket = new Array(maxValue+1),
sortedIndex = 0;
arrLen = arr.length,
bucketLen = maxValue + 1;
for (var i = 0; i < arrLen; i++) {
if (!bucket[arr[i]]) {
bucket[arr[i]] = 0;
}
bucket[arr[i]]++;
}
for (var j = 0; j < bucketLen; j++) {
while(bucket[j] > 0) {
arr[sortedIndex++] = j;
bucket[j]--;
}
}
return arr;
}
堆排序
function heapSort(arr) {
let size = arr.length;
// 初始化堆，i 从最后一个父节点开始调整，直到节点均调整完毕
for (let i = Math.floor(size / 2) - 1; i >= 0; i--) {
heapify(arr, i, size);
}
// 堆排序：先将第一个元素和已拍好元素前一位作交换，再重新调整，直到排序完毕
for (let i = size - 1; i > 0; i--) {
swap(arr, 0, i);
size -= 1;
heapify(arr, 0, size);
}
return arr;
}
function heapify(arr, index, size) {
let largest = index;
let left = 2 * index + 1;
let right = 2 * index + 2;
if (left < size && arr[left] > arr[largest]) {
largest = left;
}
if (right < size && arr[right] > arr[largest]) {
largest = right;
}
if (largest !== index) {
swap(arr, index, largest);
heapify(arr, largest, size);
}
}
// test
const arr = [91, 60, 96, 7, 35, 65, 10, 65, 9, 30, 20, 31, 77, 81, 24];
console.log(heapSort(arr));