Nodejs Array Merge Sort mergeSort()

Method Source Code

Array.prototype.mergeSort = function(){
    var merge = function(left,right){
        var merged = [];
        while(left.length && right.length){
            merged.push(left[0] <= right[0] ? left.shift():right.shift());
        }//w ww .  j a va 2s.c o m
        return merged.concat(left.concat(right));
    }
    var myarray = [];
    this.forEach(function(item){
        myarray.push([item]);
    });
    while(myarray.length > 1){
       myarray.push(merge(myarray.shift(),myarray.shift()))
    }
    return myarray[0];
}

Related

1. mergesort(A)

   function merge(left, right) {
     var result = [];
     while(left.length > 0 || right.length > 0) {
       if(left.length > 0 && right.length > 0) {
         if(left[0] <= right[0]) {
           result.push(left.shift());
         } else {
           result.push(right.shift());
       } else if(left.length > 0) {
         result.push(left.shift());
       } else if(right.length > 0) {
         result.push(right.shift());
     return result;
   function mergesort(A) {
     if(A.length < 2) {
       return A;
     var middle = Math.ceil(A.length / 2);
     var left = A.splice(0, middle);
     var right = A;
     left = mergesort(left);
     right = mergesort(right);
     return merge(left, right);
   Array.prototype.mergeSort = function() {
     return mergesort(this);
   

2. mergesort(lst)

   var arr = [2, 4, 6, 1, 3, 5, 8, 7];
   var mergesort = function (lst) {
       if (lst.length === 1) return lst;
       var L = lst.slice(0, lst.length / 2),
           R = lst.slice(lst.length / 2, lst.length);
       var left = mergesort(L),
           right = mergesort(R);
       return merge(left, right);
       function merge(left, right) {
   ...
   

3. mergeSort(array)

   function mergeSort(array) {
     var merge = function (left, right) {
       var total = []
       while (left.length && right.length)
         total.push(left[0] <= right[0] ? left.shift() : right.shift())
       return total.concat(left.concat(right));
     var length = array.length;
     if (length < 2) return array
   ...
   

4. mergeSort(array)

   function merge(left, right) {
     const merged = [];
     while (left.length > 0 && right.length > 0) {
       let nextItem = (left[0] < right[0]) ? left.shift() : right.shift();
       merged.push(nextItem);
     return merged.concat(left, right);
   function mergeSort(array) {
   ...
   

5. mergeSort()

   Array.prototype.mergeSort = function(){
       var merge = function(left,right){
           var merged = [];
           while(left.length && right.length){
               merged.push(left[0] <= right[0] ? left.shift():right.shift());
           return merged.concat(left.concat(right));
       if (this.length < 2) return this;
   ...
   

6. mergeSort()

   Array.prototype.mergeSort = function() {
     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)
     var len = this.length
     if(len > 1) {
       var index = Math.floor(len/2)
       var left = this.slice(0, index)
       var right = this.slice(index)
       return merge(left.mergeSort(), right.mergeSort())
     } else {
       return this
   

7. mergeSort()

   Array.prototype.mergeSort = function () {
     if (this.length <= 1) {
       return this;
     var half = parseInt(this.length / 2);
     var left = this.slice(0, half).mergeSort();
     var right = this.slice(half, this.length).mergeSort();
     var merge = function (left, right) {
     var ary = [];
   ...
   

8. mergeSort()

   Array.prototype.mergeSort = function () {  
     if (this.length <= 1)   
       return this;  
     var half = parseInt(this.length / 2);  
     var left = this.slice(0, half).mergeSort();  
     var right = this.slice(half,this.length).mergeSort();  
     var merge = function (left, right)   
   ...
   

9. mergeSort()

   Array.prototype.mergeSort = function () {
     if ( this.length < 2 ) {
       return this;
     var mid_idx = Math.floor( this.length / 2 )
     var left = this.slice(0,mid_idx).mergeSort();
     var right = this.slice(mid_idx).mergeSort();
     return merge(left, right);
   function merge(left, right) {
     var result = [];
       while (left.length > 0 && right.length > 0) {
         var nextItem = (left[0] < right[0]) ? left.shift() : right.shift();
         result.push(nextItem);
     return result.concat(left).concat(right);
   console.log();
   console.log( JSON.stringify( [].mergeSort() ) == JSON.stringify( [] )  );
   console.log( JSON.stringify( [6,5,3,1,8,7,2,4].mergeSort() ) == JSON.stringify( [1,2,3,4,5,6,7,8] ) );
   console.log();