JS简单实现排序算法
归并排序
function merge(left, right) {
var result = [];
while(left.length > 0 && right.length > 0) { if(left[0] < right[0]) { result.push(left.shift()); }
else { result.push(right.shift()); }
}
return result;
}
function mergeSort(arr){
if(arr.length==1) {return arr};
var mid=Math.floor(arr.length/2);
var left_arr=arr.slice(0,mid),right_arr=arr.slice(mid);
return merge(mergeSort(left_arr),mergeSort(right_arr));
}堆排序
function AdjustHeap(arr, pos, len){
var swap = arr[pos];
var child = pos * 2 + 1;
while(child < len){ if(child + 1 < len && arr[child] < arr[child + 1]){ child += 1; }
if(arr[pos] < arr[child]){ arr[pos] = arr[child]; pos = child; child = pos * 2 + 1; }
else{ break; }
arr[pos] = swap;
}
}
function HeapSort(arr){
for(var j=arr.length/2; j>=0; j--){ AdjustHeap(arr, j, arr.length); }
for(var i=arr.length-1; i>0; i--){ var swap = arr[i]; arr[i] = arr[0]; arr[0] = swap; AdjustHeap(arr, 0, i); }
}快排
function quickSort(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));
}
编写一个函数实现对Object，Array，Boolean，Number，String这五种主要数据类型进行值复制。
function clone(obj){
var o;
switch (typeof obj){
case "undefined":
break;
case "string":
o=obj+"";
break;
case "number":
o=obj-0;
break;
case "boolean":
o=obj;
break;
case "object":
if(obj===null){
o=null;
} else {
if(Object.prototype.toString.call(obj).slice(8,-1)==="Array"){
o=[];
for(var i=0;i<obj.length;i++){
o.push(clone(obj[i]));
}
} else {
o={};
for(var k in obj){
o[k] = clone(obj[k]);
}
}
}
break;
default:
o = obj;
break;
}
return o;
}冒泡排序
function BubbleSort1(arr) {
var i,j;
for(var i=0;i<arr.length-1;i++){ for(var j=arr.length-1;j>=i;j--){ if(arr[j-1]>arr[j]){ var temp=arr[j]; arr[j]=arr[j-1]; arr[j-1]=temp; }
}
}
return arr;
}//改进冒泡
function BubbleSort2(arr) {
var i,j;
var flag=true;
for(var i=0;i<arr.length-1 && flag;i++){
flag=false;
for(var j=arr.length-1;j>=i;j--){
if(arr[j-1]>arr[j]){
var temp=arr[j];
arr[j]=arr[j-1];
arr[j-1]=temp;
flag=true;
}
}
}
return arr;
}//选择排序
function SelectSort(arr) {
var i,j,min;
for(var i=0;i<arr.length-1;i++){
min=i;
for(var j=i+1;j<arr.length;j++){
if(arr[min]>arr[j])
min=j;
}
if(i!=min){
var temp=arr[min];
arr[min]=arr[i];
arr[i]=temp;
}
}
return arr;
}//直接插入排序
function InsertSort(arr) {
var i,j;
for(var i=1;i<arr.length;i++){
if(arr[i]<arr[i-1]){
var temp=arr[i];
for (var j=i-1;arr[j]>temp;j--){
arr[j+1]=arr[j];
}
arr[j+1]=temp;
}
}
return arr;
}
//插入排序
function insertionSort(arr) {
for(var i=1;i<arr.length;i++){
key=arr[i];
var j=i-1;
while ( j>=0 && arr[j]>key){
arr[j+1]=arr[j];
j=j-1;
}
arr[j+1]=key;
}
return arr;
}//希尔排序
function ShellSort(arr) {
var i,j;
var increment=arr.length;
while (increment>1){
increment=Math.floor(increment/3)+1;
for(i=increment;i<arr.length;i++){
if(arr[i]<arr[i-increment]){
var tmp=arr[i];
for(j=i-increment;j>=0&&tmp<arr[j];j-=increment){
arr[j+increment]=arr[j];
}
arr[j+increment]=tmp;
}
}
}
return arr;
}//堆排序
function HeapSort(arr) {
var i;
for(i=Math.floor(arr.length/2);i>=0;i--){
HeapAjust(arr,i,arr.length);
}
for (i=arr.length-1;i>0;i--){
var temp=arr[0];
arr[0]=arr[i];
arr[i]=temp;
HeapAjust(arr,0,i-1);
}
return arr;
}
function HeapAjust(arr,s,m) {
var temp;
temp=arr[s];
for(var j=2*s;j<=m;j*=2){
if((j<m) && (arr[j]<arr[j+1])){
++j;
}
if(temp>=arr[j]){
break;
}
arr[s]=arr[j];
s=j;
}
arr[s]=temp;
}//归并排序 递归方式
function mergeSort(arr){
var len = arr.length;
if(len > 1){
var index = Math.floor(len / 2);
var left = arr.slice(0, index), right = arr.slice(index);
return merge(mergeSort(left), mergeSort(right));
}else{
return arr;
}
}
function merge(left, right){
var arr = [];
while(left.length && right.length){
if(left[0] < right[0]){
arr.push(left.shift());
}else{
arr.push(right.shift());
}
}
return arr.concat(left, right);
}
//归并排序
//大辉版
function MergeSort(arr) {
MSort(arr,arr,0,arr.length-1);
}
function MergeSort(arr) {
MSort(arr,0,arr.length-1);
return arr;
}
//将SR归并排序为result
function MSort(arr,s,t) {
if(s==t){
return;
} else {
var m=Math.floor((s+t)/2);
MSort(arr,s,m);
MSort(arr,m+1,t);
Merge(arr,s,m,t);
}
}
//SR源数组，SR[i,m],SR[m+1,n]组合为TR[i,n]
function Merge(arr,left,mid,right) {
var i,j,k;
var temp=[];
i=left;
j=mid+1;
k=0;
while(i<=mid&&j<=right){
if(arr[i]<arr[j]){
temp[k++]=arr[i++];
} else {
temp[k++]=arr[j++];
}
}
while(i<=mid){
temp[k++]=arr[i++];
}
while(j<=right){
temp[k++]=arr[j++];
}
k=0;
for(i=left;i<=right;i++){
arr[i]=temp[k++];
}
}
//归并排序 课本递归版
function MergeSort(arr) {
var TR1=[];
MSort(arr,TR1,0,arr.length-1);
return TR1;
}
//将SR归并排序为result
function MSort(SR,TR1,s,t) {
var m;
var TR2=[];
if(s==t){
TR1[s]=SR[s];
} else {
var m=Math.floor((s+t)/2);
MSort(SR,TR2,s,m);
MSort(SR,TR2,m+1,t);
Merge(TR2,TR1,s,m,t);
}
}
//SR源数组，SR[i,m],SR[m+1,n]组合为TR[i,n]
function Merge(SR,TR,i,m,n) {
var j,l;
var k=0;
for(j=m+1,k=i;i<=m&&j<=n;k++){
if(SR[i]<SR[j]){
TR[k]=SR[i++];
} else {
TR[k]=SR[j++];
}
}
if(i<=m){
for(l=0;l<=m-i;l++){
TR[k+l]=SR[i+l];
}
}
if(j<=n){
for(l=0;l<=n-j;l++){
TR[k+l]=SR[j+l];
}
}
// return TR;
}//归并排序 课本非递归版
function MergeSort2(arr) {
var TR=[];
var k=1;
while (k<arr.length){
MergePass(arr,TR,k,arr.length);
k=2*k;
MergePass(TR,arr,k,arr.length);
k=2*k;
}
return arr;
}
function MergePass(SR,TR,s,n) {
var i=0;
var j;
while (i<=n-2*s){
Merge(SR,TR,i,i+s-1,i+2*s-1);
i=i+2*s;
}
if(i<n-s){
Merge(SR,TR,i,i+s-1,n-1);
} else {
for(j=i;j<=n-1;j++){
TR[j]=SR[j];
}
}
}
function Merge(SR,TR,i,m,n) {
var j,l;
var k=0;
for(j=m+1,k=i;i<=m&&j<=n;k++){
if(SR[i]<SR[j]){
TR[k]=SR[i++];
} else {
TR[k]=SR[j++];
}
}
if(i<=m){
for(l=0;l<=m-i;l++){
TR[k+l]=SR[i+l];
}
}
if(j<=n){
for(l=0;l<=n-j;l++){
TR[k+l]=SR[j+l];
}
}
}//快排 课本版
function QuickSort(arr){
if(arr.length <= 1){
return arr;
}
// 从中间取一个数
var index = Math.floor(arr.length / 2);
// 被选中的一个数
//arr.splice返回的是一个数组
var key = arr.splice(index, 1)[0];
var left = [], right = [];
for(var i = 0; i < arr.length; i++){
if(arr[i] < key){
left.push(arr[i]);
}else{
right.push(arr[i]);
}
}
return QuickSort(left).concat(key, QuickSort(right));
}
// console.log(QuickSort([2,1,5,3,7,4,8,6,9]));
function QuickSort(arr) {
QSort(arr,0,arr.length-1);
return arr;
}
//对序列表中子序列作快排
function QSort(arr,low,high) {
var pivot;
if(low<high){
pivot=Partion(arr,low,high);
QSort(arr,low,pivot-1);
QSort(arr,pivot+1,high);
}
}
//返回枢轴所在位置
function Partion(arr,low,high) {
pivotkey=arr[low];
while (low<high){
while (low<high&&arr[high]>=pivotkey){
high--;
}
var temp=arr[low];
arr[low]=arr[high];
arr[high]=temp;
while (low<high&&arr[low]<=pivotkey){
low++;
}
var temp=arr[low];
arr[low]=arr[high];
arr[high]=temp;
}
return low;
}
//快排优化
function QuickSort(arr) {
QSort(arr,0,arr.length-1);
return arr;
}
//对序列表中子序列作快排
function QSort(arr,low,high) {
var pivot;
if(low<high){
pivot=Partion(arr,low,high);
QSort(arr,low,pivot-1);
QSort(arr,pivot+1,high);
}
}
//返回枢轴所在位置
function Partion(arr,low,high) {
var pivotkey;
var m=low+(high-low)/2;
if(arr[low]>arr[high]){
var temp=arr[low];
arr[low]=arr[high];
arr[high]=temp;
}
if(arr[m]>arr[high]){
var temp=arr[high];
arr[high]=arr[m];
arr[m]=temp;
}
if(arr[m]>arr[low]){
var temp=arr[low];
arr[low]=arr[m];
arr[m]=temp;
}
pivotkey=arr[low];
while (low<high){
while (low<high&&arr[high]>=pivotkey){
high--;
}
var temp=arr[low];
arr[low]=arr[high];
arr[high]=temp;
while (low<high&&arr[low]<=pivotkey){
low++;
}
var temp=arr[low];
arr[low]=arr[high];
arr[high]=temp;
}
return low;
}
//再优化
function QuickSort(arr) {
QSort(arr,0,arr.length-1);
return arr;
}
//对序列表中子序列作快排
function QSort(arr,low,high) {
var pivot;
if(low<high){
pivot=Partion(arr,low,high);
QSort(arr,low,pivot-1);
QSort(arr,pivot+1,high);
}
}
//返回枢轴所在位置
function Partion(arr,low,high) {
var pivotkey;
var m=low+(high-low)/2;
if(arr[low]>arr[high]){
var temp=arr[low];
arr[low]=arr[high];
arr[high]=temp;
}
if(arr[m]>arr[high]){
var temp=arr[high];
arr[high]=arr[m];
arr[m]=temp;
}
if(arr[m]>arr[low]){
var temp=arr[low];
arr[low]=arr[m];
arr[m]=temp;
}
pivotkey=arr[low];
var num=pivotkey;
while (low<high){
while (low<high&&arr[high]>=pivotkey){
high--;
}
arr[low]=arr[high];
while (low<high&&arr[low]<=pivotkey){
low++;
}
arr[high]=arr[low];
}
arr[low]=num;
return low;
}二分查找
递归实现
function search(arr,low,high, key) {
var mid = parseInt((high + low) / 2);
if(arr[mid] == key){
return mid;
}else if (arr[mid] > key){
high = mid - 1;
return binary_search(arr, low, high, key);
}else if (arr[mid] < key){
low = mid + 1;
return binary_search(arr, low, high, key);
}
}非递归实现
function search(arr,key) {
var low,mid,high;
low=0;
high=arr.length;
while (low<=high){
mid=parseInt(low+high)/2;
if(key<a[mid]){
high=mid-1;
} else if (key>a[mid]){
low=mid+1;
}
else
return mid;
}
}