js的几种排序
转载:http://www.jb51.net/article/81520.htm
一.冒泡排序 平均情况n方,最好n,最差n方
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function BubbleSort(array) { var length = array.length; for ( var i = length - 1; i > 0; i--) { //用于缩小范围 for ( var j = 0; j < i; j++) { //在范围内进行冒泡,在此范围内最大的一个将冒到最后面 if (array[j] > array[j+1]) { var temp = array[j]; array[j] = array[j+1]; array[j+1] = temp; } } console.log(array); console.log( "-----------------------------" ); } return array; } var arr = [10,9,8,7,7,6,5,11,3]; var result = BubbleSort(arr); console.log(result); /* [ 9, 8, 7, 7, 6, 5, 10, 3, 11 ] ----------------------------- [ 8, 7, 7, 6, 5, 9, 3, 10, 11 ] ----------------------------- [ 7, 7, 6, 5, 8, 3, 9, 10, 11 ] ----------------------------- [ 7, 6, 5, 7, 3, 8, 9, 10, 11 ] ----------------------------- [ 6, 5, 7, 3, 7, 8, 9, 10, 11 ] ----------------------------- [ 5, 6, 3, 7, 7, 8, 9, 10, 11 ] ----------------------------- [ 5, 3, 6, 7, 7, 8, 9, 10, 11 ] ----------------------------- [ 3, 5, 6, 7, 7, 8, 9, 10, 11 ] ----------------------------- [ 3, 5, 6, 7, 7, 8, 9, 10, 11 ] */ |
二.选择排序 平均n方,最好n方,最差n方
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function SelectionSort(array) { var length = array.length; for ( var i = 0; i < length; i++) { //缩小选择的范围 var min = array[i]; //假定范围内第一个为最小值 var index = i; //记录最小值的下标 for ( var j = i + 1; j < length; j++) { //在范围内选取最小值 if (array[j] < min) { min = array[j]; index = j; } } if (index != i) { //把范围内最小值交换到范围内第一个 var temp = array[i]; array[i] = array[index]; array[index] = temp; } console.log(array); console.log( "---------------------" ); } return array; } var arr = [ 1, 10, 100, 90, 65, 5, 4, 10, 2, 4 ]; var result = SelectionSort(arr); console.log(result); /* [ 1, 10, 100, 90, 65, 5, 4, 10, 2, 4 ] --------------------- [ 1, 2, 100, 90, 65, 5, 4, 10, 10, 4 ] --------------------- [ 1, 2, 4, 90, 65, 5, 100, 10, 10, 4 ] --------------------- [ 1, 2, 4, 4, 65, 5, 100, 10, 10, 90 ] --------------------- [ 1, 2, 4, 4, 5, 65, 100, 10, 10, 90 ] --------------------- [ 1, 2, 4, 4, 5, 10, 100, 65, 10, 90 ] --------------------- [ 1, 2, 4, 4, 5, 10, 10, 65, 100, 90 ] --------------------- [ 1, 2, 4, 4, 5, 10, 10, 65, 100, 90 ] --------------------- [ 1, 2, 4, 4, 5, 10, 10, 65, 90, 100 ] --------------------- [ 1, 2, 4, 4, 5, 10, 10, 65, 90, 100 ] --------------------- [ 1, 2, 4, 4, 5, 10, 10, 65, 90, 100 ] */ |
三.插入排序 平均n方 最好n 最差 n方
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function InsertionSort(array) { var length = array.length; for ( var i = 0; i < length - 1; i++) { //i代表已经排序好的序列最后一项下标 var insert = array[i+1]; var index = i + 1; //记录要被插入的下标 for ( var j = i; j >= 0; j--) { if (insert < array[j]) { //要插入的项比它小,往后移动 array[j+1] = array[j]; index = j; } } array[index] = insert; console.log(array); console.log( "-----------------------" ); } return array; } var arr = [100,90,80,62,80,8,1,2,39]; var result = InsertionSort(arr); console.log(result); /* [ 90, 100, 80, 62, 80, 8, 1, 2, 39 ] ----------------------- [ 80, 90, 100, 62, 80, 8, 1, 2, 39 ] ----------------------- [ 62, 80, 90, 100, 80, 8, 1, 2, 39 ] ----------------------- [ 62, 80, 80, 90, 100, 8, 1, 2, 39 ] ----------------------- [ 8, 62, 80, 80, 90, 100, 1, 2, 39 ] ----------------------- [ 1, 8, 62, 80, 80, 90, 100, 2, 39 ] ----------------------- [ 1, 2, 8, 62, 80, 80, 90, 100, 39 ] ----------------------- [ 1, 2, 8, 39, 62, 80, 80, 90, 100 ] ----------------------- [ 1, 2, 8, 39, 62, 80, 80, 90, 100 ] */ |
四.希尔排序(shell排序)每一种巧妙算法的本质是利用了一种巧合,shell算法的平均时间是nlog2n说明,他的本质和快速排序是一样的,只不过他的形式不同,不过 有一点相同的,他们都分为2分之一这种思想,不过shell更巧合一点。
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function ShellSort(array) { var length = array.length; var gap = Math.round(length / 2); while (gap > 0) { for ( var i = gap; i < length; i++) { var insert = array[i]; var index = i; for ( var j = i; j >= 0; j-=gap) { if (insert < array[j]) { array[j+gap] = array[j]; index = j; } } array[index] = insert; } console.log(array); console.log( "-----------------------" ); gap = Math.round(gap/2 - 0.1); } return array; } var arr = [ 13, 14, 94, 33, 82, 25, 59, 94, 65, 23, 45, 27, 73, 25, 39, 10 ]; var result = ShellSort(arr); console.log(result); /* [ 13, 14, 45, 27, 73, 25, 39, 10, 65, 23, 94, 33, 82, 25, 59, 94 ] ----------------------- [ 13, 14, 39, 10, 65, 23, 45, 27, 73, 25, 59, 33, 82, 25, 94, 94 ] ----------------------- [ 13, 10, 39, 14, 45, 23, 59, 25, 65, 25, 73, 27, 82, 33, 94, 94 ] ----------------------- [ 10, 13, 14, 23, 25, 25, 27, 33, 39, 45, 59, 65, 73, 82, 94, 94 ] ----------------------- [ 10, 13, 14, 23, 25, 25, 27, 33, 39, 45, 59, 65, 73, 82, 94, 94 ] */ |
五.归并排序
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function MergeSort(array) { var length = array.length; if (length <= 1) { return array; } else { var num = Math.ceil(length/2); var left = MergeSort(array.slice(0, num)); var right = MergeSort(array.slice(num, length)); return merge(left, right); } } function merge(left, right) { console.log(left); console.log(right); var a = new Array(); while (left.length > 0 && right.length > 0) { if (left[0] <= right[0]) { var temp = left.shift(); a.push(temp); } else { var temp = right.shift(); a.push(temp); } } if (left.length > 0) { a = a.concat(left); } if (right.length > 0) { a = a.concat(right); } console.log(a); console.log( "-----------------------------" ); return a; } var arr = [ 13, 14, 94, 33, 82, 25, 59, 94, 65, 23, 45, 27, 73, 25, 39, 10 ]; var result = MergeSort(arr); console.log(result); /* [ 13 ] [ 14 ] [ 13, 14 ] ----------------------------- [ 94 ] [ 33 ] [ 33, 94 ] ----------------------------- [ 13, 14 ] [ 33, 94 ] [ 13, 14, 33, 94 ] ----------------------------- [ 82 ] [ 25 ] [ 25, 82 ] ----------------------------- [ 59 ] [ 94 ] [ 59, 94 ] ----------------------------- [ 25, 82 ] [ 59, 94 ] [ 25, 59, 82, 94 ] ----------------------------- [ 13, 14, 33, 94 ] [ 25, 59, 82, 94 ] [ 13, 14, 25, 33, 59, 82, 94, 94 ] ----------------------------- [ 65 ] [ 23 ] [ 23, 65 ] ----------------------------- [ 45 ] [ 27 ] [ 27, 45 ] ----------------------------- [ 23, 65 ] [ 27, 45 ] [ 23, 27, 45, 65 ] ----------------------------- [ 73 ] [ 25 ] [ 25, 73 ] ----------------------------- [ 39 ] [ 10 ] [ 10, 39 ] ----------------------------- [ 25, 73 ] [ 10, 39 ] [ 10, 25, 39, 73 ] ----------------------------- [ 23, 27, 45, 65 ] [ 10, 25, 39, 73 ] [ 10, 23, 25, 27, 39, 45, 65, 73 ] ----------------------------- [ 13, 14, 25, 33, 59, 82, 94, 94 ] [ 10, 23, 25, 27, 39, 45, 65, 73 ] [ 10, 13, 14, 23, 25, 25, 27, 33, 39, 45, 59, 65, 73, 82, 94, 94 ] ----------------------------- [ 10, 13, 14, 23, 25, 25, 27, 33, 39, 45, 59, 65, 73, 82, 94, 94 ] */ |
六.快速排序 平均情况nlog2n 最好情况nlog2n 最差n2
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function QuickSort(array) { var length = array.length; if (length <= 1) { return array; } else { var smaller = []; var bigger = []; var base = [array[0]]; for ( var i = 1; i < length; i++) { if (array[i] <= base[0]) { smaller.push(array[i]); } else { bigger.push(array[i]); } } console.log(smaller.concat(base.concat(bigger))); console.log( "-----------------------" ); return QuickSort(smaller).concat(base.concat(QuickSort(bigger))); } } var arr = [ 8, 10, 100, 90, 65, 5, 4, 10, 2, 4 ]; var result = QuickSort(arr); console.log(result); /* [ 5, 4, 2, 4, 8, 10, 100, 90, 65, 10 ] ----------------------- [ 4, 2, 4, 5 ] ----------------------- [ 2, 4, 4 ] ----------------------- [ 2, 4 ] ----------------------- [ 10, 10, 100, 90, 65 ] ----------------------- [ 90, 65, 100 ] ----------------------- [ 65, 90 ] ----------------------- [ 2, 4, 4, 5, 8, 10, 10, 65, 90, 100 ] */ |
我们可以看百度百科的解释
有一篇java的快速排序,感觉比这个还好
代码:
function quickSort(arr, left, right) { var len = arr.length, partitionIndex, left = typeof left != 'number' ? 0 : left, right = typeof right != 'number' ? len - 1 : right; if (left < right) { partitionIndex = partition(arr, left, right); quickSort(arr, left, partitionIndex-1); quickSort(arr, partitionIndex+1, right); } return arr; } function partition(arr, left ,right) { //分区操作 var pivot = left, //设定基准值(pivot) index = pivot + 1; for (var i = index; i <= right; i++) { if (arr[i] < arr[pivot]) { swap(arr, i, index); index++; } } swap(arr, pivot, index - 1); return index-1; } function swap(arr, i, j) { var temp = arr[i]; arr[i] = arr[j]; arr[j] = temp; }
上面这个快排序有一个奇怪的现象。
我写成 left = left|| 0;这样子就报错了,我没找到原因。以后有时间请人看看吧。