javascript常见排序算法总结

javascript常见排序算法总结

　　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：

function merge(left, right){     var result  = [],         il      = 0,         ir      = 0;      while (il < left.length && ir < right.length){         if (left[il] < right[ir]){             result.push(left[il++]);         } else {             result.push(right[ir++]);         }     }      return result.concat(left.slice(il)).concat(right.slice(ir)); }

function mergeSort(items){      // 结束条件: 数组元素少于2个     if (items.length < 2) {         return items;     }      var middle = Math.floor(items.length / 2),         left   = items.slice(0, middle),         right  = items.slice(middle);      return merge(mergeSort(left), mergeSort(right)); }

function mergeSort2(items){      if (items.length < 2) {         return items;     }      var middle = Math.floor(items.length / 2),         left   = items.slice(0, middle),         right  = items.slice(middle),         params = merge(mergeSort(left), mergeSort(right));          params.unshift(0, items.length);     items.splice.apply(items, params);     return items; }

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：

function swap(items, firstIndex, secondIndex){     var temp = items[firstIndex];     items[firstIndex] = items[secondIndex];     items[secondIndex] = temp; }

function selectionSort(items){      var len = items.length,         min;      for (i=0; i < len; i++){         min = i;         for (j=i+1; j < len; j++){             if (items[j] < items[min]){                 min = j;             }         }          if (i != min){             swap(items, i, min);         }     }      return items; }

冒泡排序：

function swap(items, firstIndex, secondIndex){     var temp = items[firstIndex];     items[firstIndex] = items[secondIndex];     items[secondIndex] = temp; }

function bubbleSort(items){      var len = items.length,         i, j, stop;      for (i=0; i < len; i++){         for (j=0, stop=len-i; j < stop; j++){             if (items[j] > items[j+1]){                 swap(items, j, j+1);             }         }     }      return items; }

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：

function binarySearch(items, value){      var startIndex  = 0,         stopIndex   = items.length - 1,         middle      = Math.floor((stopIndex + startIndex)/2);      while(items[middle] != value && startIndex < stopIndex){          if (value < items[middle]){             stopIndex = middle - 1;         } else if (value > items[middle]){             startIndex = middle + 1;         }          middle = Math.floor((stopIndex + startIndex)/2);     }      return (items[middle] != value) ? -1 : middle; }

基数排序：

var countSort = function(array) {   var i, z = 0, count = [],   min = Math.min.apply({}, array),   max = Math.max.apply({}, array),   size = array.length;   //给新数组预填为零   for (i = min; i <= max; i++) {     count[i] = 0;   }   for (i=0; i < size; i++) {     count[array[i]]++;   }     for (i = min; i <= max; i++) {     while (count[i]-- > 0) {//循环新数组，如果不为零，则把i返回array       array[z++] = i;     }   }   return array; }

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：

var combSort = function(array){   var gap = array.length;   do{     gap = gap * 10 / 13     if(gap === 9 || gap === 10)       gap = 11     if(gap < 1){       gap = 1     }     var swapped = false;     for(var i=0;i<array.length-gap;i++){       var j = i + gap       if(array[i]>array[j]){         var temp = array[i];         array[i] = array[j];         array[j] = temp;         test(array)         swapped = true       }     }     if(gap == 1 && !swapped){       break;     }   }while(1); }

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;}

转自：http://www.cnblogs.com/chenguangyin/archive/2012/11/19/2777757.html