8大排序算法总结 JS 实现

//bubble sort

function bubbleSort(arr,comp){

for(var i = 0;i < arr.length; i++){
for(var j = 0; j < arr.length - i - 1; j++){
if(comp(arr[j],arr[j+1])){
exch(arr,j,j+1);
}
}
}

}

function exch(a,i,j){
var tmp = a[i];
a[i] = a[j];
a[j] = tmp;
}

var input = new Array(5,1,4,2,3);
bubbleSort(input,function(a,b){return a > b;});
console.log(input);

input = new Array(5,1,4,2,3);
bubbleSort(input,function(a,b){return a < b;});
console.log(input);

//selection sort

function selectionSort(arr,comp){

for(var i = 0;i < arr.length ; i++){
for(var j = i;j < arr.length ; j++){
if(comp(arr[i],arr[j])) { exch(arr,i,j); }
}
}

}

function exch(a,i,j){
var t = a[i];
a[i] = a[j];
a[j] = t;
}

var input = new Array(5,1,4,2,3);
selectionSort(input,function(a,b){return a > b;});
console.log(input);

input = new Array(5,1,4,2,3);
bubbleSort(input,function(a,b){return a < b;});
console.log(input);

//insert sort

function insertSort(arr,comp){
var result = new Array();
for(;arr.length > 0;){

var inserted = false;
for(var j = 0;j < result.length; j++){
if(comp(result[j],arr[0])) { insert(result,j,arr[0]); inserted = true; break;}
}
if(!inserted){insert(result,result.length,arr[0]);}
arr.splice(0,1);
}
return result;
}

function insert(arr,i,v){
arr.splice(i,0,v);
}

var input = new Array(5,1,4,2,3);
var ret = insertSort(input,function(a,b){return a > b;});
console.log(ret);

var input = new Array(5,1,4,2,3);
ret = insertSort(input,function(a,b){return a < b;});
console.log(ret);

//shell sort

function shellSort (a,comp) {
    for (var h = a.length; h = parseInt(h / 2);) {
        for (var i = h; i < a.length; i++) {
            var k = a[i];
            for (var j = i; j >= h && comp(k, a[j - h]); j -= h)
                a[j] = a[j - h];
            a[j] = k;
        }
    }
    return a;
}

var arr =new Array(7,9,2,5,4,1,3);
var r = shellSort(arr,function (a,b){return a > b;});
console.log(r);

//merge sort

function mergeS(arr,comp){

if(arr.length == 1){return arr;}

var mid = arr.length / 2 | 0;
var leftArr = new Array();
var rightArr = new Array();
for(var i = 0;i < mid;i ++){
leftArr.push(arr[i]);
}

for(var j = mid;j < arr.length; j++){
rightArr.push(arr[j]);
}

console.log("before : " + leftArr + " | " + rightArr);
var leftRet = mergeS(leftArr,comp);
var rightRet = mergeS(rightArr,comp);

var r = merge(leftRet,rightRet,comp);
return r;
}

function merge(leftArr,rightArr,comp){

var ret = new Array();
var i = j = 0;
for(;i < leftArr.length && j < rightArr.length; ){
if(comp(leftArr[i],rightArr[j])){ret.push(leftArr[i]); i ++}
else {ret.push(rightArr[j]); j ++}
}

for(;i < leftArr.length;){
ret.push(leftArr[i]);i++;
}
for(;j< rightArr.length; ){
ret.push(rightArr[j]);j++;
}

return ret;

}

var r = mergeS(new Array(0,6,5,1,2,4,3,9),function(a,b){return a > b;});
console.log(r);

//quick sort

function quickS(arr,lo,hi,comp){
if(lo >= hi){return ;}

var stub = arr[lo];

var i = lo + 1;
var j = hi;

for(;i < j ;){
for(;i < j && !comp(stub,arr[j]);j--);
for(;i < j && comp(stub,arr[i]);i++);

if(i >= j){break;}

var t = arr[i];
arr[i] = arr[j];
arr[j] = t;

j--;
i++;
}

if(comp(arr[lo],arr[i])){
var t = arr[lo];
arr[lo] = arr[i];
arr[i] = t;
}

quickS(arr,lo,i-1,comp);
quickS(arr,i,hi,comp);
}

var input = new Array(22,3,10,66,15,11,2,4,31,9);
quickS(input, 0, input.length - 1,function(a,b){return a > b;});
console.log(input);

//heap sort

var ret = new Array();
function heapS(arr,comp){
if(arr.length == 0){return ;}
var i = arr.length / 2 | 0 ;
for(;i >= 0; i--){
if(comp(arr[i], arr[i * 2])){exch(arr, i, i*2);}
if(comp(arr[i], arr[i * 2 + 1])) {exch(arr, i, i*2 + 1);}
}
ret.push(arr[0]);
arr.splice(0,1);
heapS(arr,comp);
}

function exch(arr,i,j){
var t = arr[i];
arr[i] = arr[j];
arr[j] = t;
}

heapS(new Array(16,22,91,0,51,44,23),function (a,b){return a > b;});
console.log(ret);