算法是程序的灵魂。虽然在前端的开发环境中排序算法不是很经常用到，但常见的排序算法还是应该要掌握的。我在这里从网上整理了一下常见排序算法的javascript实现，方便以后查阅。
归并排序：
1 function merge(left, right){ 2 var result = [], 3 il = 0, 4 ir = 0; 5 6 while (il < left.length && ir < right.length){ 7 if (left[il] < right[ir]){ 8 result.push(left[il++]); 9 } else { 10 result.push(right[ir++]); 11 } 12 } 13 14 return result.concat(left.slice(il)).concat(right.slice(ir)); 15 }
1 function mergeSort(items){ 2 3 // 结束条件: 数组元素少于2个 4 if (items.length < 2) { 5 return items; 6 } 7 8 var middle = Math.floor(items.length / 2), 9 left = items.slice(0, middle), 10 right = items.slice(middle); 11 12 return merge(mergeSort(left), mergeSort(right)); 13 }
1 function mergeSort2(items){ 2 3 if (items.length < 2) { 4 return items; 5 } 6 7 var middle = Math.floor(items.length / 2), 8 left = items.slice(0, middle), 9 right = items.slice(middle), 10 params = merge(mergeSort(left), mergeSort(right)); 11 12 params.unshift(0, items.length); 13 items.splice.apply(items, params); 14 return items; 15 }
插入排序：
function insertionSort(items) { var len = items.length, value, i, j; for (i=0; i < len; i++) { value = items[i]; for (j=i-1; j > -1 && items[j] > value; j--) { items[j+1] = items[j]; } items[j+1] = value; } return items; }
选择排序：
1 function swap(items, firstIndex, secondIndex){ 2 var temp = items[firstIndex]; 3 items[firstIndex] = items[secondIndex]; 4 items[secondIndex] = temp; 5 }
1 function selectionSort(items){ 2 3 var len = items.length, 4 min; 5 6 for (i=0; i < len; i++){ 7 min = i; 8 for (j=i+1; j < len; j++){ 9 if (items[j] < items[min]){ 10 min = j; 11 } 12 } 13 14 if (i != min){ 15 swap(items, i, min); 16 } 17 } 18 19 return items; 20 }
冒泡排序：
1 function swap(items, firstIndex, secondIndex){ 2 var temp = items[firstIndex]; 3 items[firstIndex] = items[secondIndex]; 4 items[secondIndex] = temp; 5 }
1 function bubbleSort(items){ 2 3 var len = items.length, 4 i, j, stop; 5 6 for (i=0; i < len; i++){ 7 for (j=0, stop=len-i; j < stop; j++){ 8 if (items[j] > items[j+1]){ 9 swap(items, j, j+1); 10 } 11 } 12 } 13 14 return items; 15 }
快速排序：
var quickSort = function(arr) { if (arr.length <= 1) { return arr; } var pivotIndex = Math.floor(arr.length / 2); var pivot = arr.splice(pivotIndex, 1)[0]; var left = []; var right = []; for (var i = 0; i < arr.length; i++){ if (arr[i] < pivot) { left.push(arr[i]); } else { right.push(arr[i]); } } return quickSort(left).concat([pivot], quickSort(right)); };
二分法查找：
1 function binarySearch(items, value){ 2 3 var startIndex = 0, 4 stopIndex = items.length - 1, 5 middle = Math.floor((stopIndex + startIndex)/2); 6 7 while(items[middle] != value && startIndex < stopIndex){ 8 9 if (value < items[middle]){ 10 stopIndex = middle - 1; 11 } else if (value > items[middle]){ 12 startIndex = middle + 1; 13 } 14 15 middle = Math.floor((stopIndex + startIndex)/2); 16 } 17 18 return (items[middle] != value) ? -1 : middle; 19 }
基数排序：
1 var countSort = function(array) { 2 var i, z = 0, count = [], 3 min = Math.min.apply({}, array), 4 max = Math.max.apply({}, array), 5 size = array.length; 6 //给新数组预填为零 7 for (i = min; i <= max; i++) { 8 count[i] = 0; 9 } 10 for (i=0; i < size; i++) { 11 count[array[i]]++; 12 } 13 14 for (i = min; i <= max; i++) { 15 while (count[i]-- > 0) {//循环新数组，如果不为零，则把i返回array 16 array[z++] = i; 17 } 18 } 19 return array; 20 }
希尔排序：
function shellSort(array) { var j, i, v, h=1, s=3, k,n = array.length; var result = ""; var count = 0; while(h < n) h=s*h+1; while(h > 1) { h=(h-1)/s; for (k=0; k<h; k++) for (i=k+h,j=i; i<n; i+=h, j=i) { v=array[i]; while(true) if ((j-=h) >= 0 && array[j] > v) array[j+h]=array[j]; else break; array[j+h]=v; } count++; result += "<br />第" + count + "遍排序的结果是:"; for (var n = 0; n < array.length; n++) { result += array[n] + ","; } } return result; }
组合排序：
1 var combSort = function(array){ 2 var gap = array.length; 3 do{ 4 gap = gap * 10 / 13 5 if(gap === 9 || gap === 10) 6 gap = 11 7 if(gap < 1){ 8 gap = 1 9 } 10 var swapped = false; 11 for(var i=0;i<array.length-gap;i++){ 12 var j = i + gap 13 if(array[i]>array[j]){ 14 var temp = array[i]; 15 array[i] = array[j]; 16 array[j] = temp; 17 test(array) 18 swapped = true 19 } 20 } 21 if(gap == 1 && !swapped){ 22 break; 23 } 24 }while(1); 25 }
鸡尾酒排序：
var cocktailSort= function(array) { var top = array.length - 1, bottom = 0,flag = true,i, j; while (flag) { flag = false; //从左到右到大，把最大的放到每次范围的最右边 for (i = bottom; i < top; i++) { if (array[i] > array[i + 1]) { swap(array, i, i + 1); flag = true; } } top--; //从右到到左，把最小的放到每次范围的最小边 for (j = top; j > bottom; j--) { if (array[j] < array[j - 1]) { swap(array, j, j - 1); flag = true; } } bottom++; } } var swap = function(array,a,b){ var tmp = array[a]; array[a] = array[b] array[b] = tmp; }