Nodejs Array Merge Sort mergesort(A)

Method Source Code

/**/*w  w w . j  a  v a2 s .  c  o  m*/
 * MergeSort Javascript implementation
 *  - Best: nlog(n) / Average: nlog(n) / Worst: nlog(n)
 *  - Memory: n / Stable
 *
 * @author: Sebastian Kim
 */


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);
}

Related

1. mergeSort(arr)

   var mergeSort = function (arr) {
       var n = parseInt(arr.length/2);
       if(n < 1){
           return arr;
       }else{
           var arr1 = mergeSort(arr.slice(0, n));
           var arr2 = mergeSort(arr.slice(n));
       var a = [];
   ...
   

2. mergesort (arr, lo, hi)

   'use strict';
   Array.prototype.swap = function (i, j) {
     const temp = this[i];
     this[i] = this[j];
     this[j] = temp;
   function mergesort (arr, lo, hi) {
     function partition (lo, hi) {
       if (lo >= hi) return;
   ...
   

3. 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) {
   ...
   

4. 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
   ...
   

5. 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) {
   ...
   

6. 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;
   ...