Nodejs Array Search Binary binarySearch(val)

Method Source Code

Array.prototype.binarySearch = function(val){
  var keeper = 0;
  var answer = -1;
  function recursive(arr){
    var len = arr.length;
    var start = Math.floor(len / 2);
    var current = arr[start];
    if (current === val){
      answer = start + keeper;/* w ww.j  a  v  a  2 s. c o  m*/
    } else if (current > val) {
      console.log(arr.slice(0, start));
      recursive(arr.slice(0, start));
    } else if (current < val){
      console.log(arr.slice(start, len));
      keeper += start;
      recursive(arr.slice(start, len));
    }
  }
  recursive(this);
  return answer;
};

module.exports = { Array };

Related

1. binaryIndexOfbinaryIndexOf;

   function binaryIndexOf(searchElement, map) {
     'use strict';
     if (map === undefined) map = index => this[index]
     var minIndex = 0;
     var maxIndex = this.length - 1;
     var currentIndex;
     var currentElement;
     var resultIndex;
     while (minIndex <= maxIndex) {
   ...
   

2. binarySearch(n)

   "use strict";
   var assert = require('assert'); 
   Array.prototype.binarySearch = function(n) {
     var O = Object(this);
     var f = function(lo,hi) {
       var mid = Math.floor((lo + hi) / 2);
       if (O[mid] === n) {
         return mid;
       if (lo === mid || hi === mid) {
         return -(mid+1);
       if(O[mid] < n) {
         return f(mid,hi);
       if (O[mid] > n) {
         return f(lo,mid);
     };
     return f(0, O.length);
   };
   describe('binary search', function() {
     it('doesnt find anything in an empty list', function() {
       assert.equal(-1, [].binarySearch(7));
     });
     it('finds a single element', function() {
       assert.equal(0, [0].binarySearch(0));
     });
     it('finds the middle element', function() {
       assert.equal(1, [1,2,3].binarySearch(2));
     });
     it('finds up', function() {
       assert.equal(2, [1,2,3].binarySearch(3));
     });
     it('finds down', function() {
       assert.equal(0, [1,2,3].binarySearch(1));
     });
     it('finds insertion index', function() {
       assert.equal(-2, [1,2,4,5,6].binarySearch(3));
     });
   });
   

3. binarySearch(num)

   var input = [ 1, 2, 2, 3, 4, 4, 5, 6, 8, 10 ];
   Array.prototype.binarySearch = function(num) {
       var _this = this;
       function search(left, right) {
           if(right < left) return -1;
           else if(left === right) {
               return checkIndexForNum(left);
           var mid = Math.floor((left + right) / 2);
   ...
   

4. binarySearch(searchElement)

   Array.prototype.binarySearch = function (searchElement) {
       'use strict';
       var minIndex = 0;
       var maxIndex = this.length - 1;
       var currentIndex;
       var currentElement;
       while (minIndex <= maxIndex) {
           currentIndex = (minIndex + maxIndex) / 2 | 0;
           currentElement = this[currentIndex];
   ...
   

5. binarySearch(val)

   Array.prototype.binarySearch = function(val){
     var min = 0;
     var max = this.length -1;
     var currentIndex;
     var currentElement;
     while (min <= max) {
       currentIndex = Math.floor((min +max) / 2);
       currentElement = this[currentIndex];
       if (currentElement > val) {
   ...
   

6. binarySearch(value)

   Array.prototype.binarySearch = function(value) {
       'use strict';
       if(!value){
           return null;
       var left = 0,
           right = this.length-1,
           find = false,
           middle = null;
   ...
   

7. binarySearch(value)

   Array.prototype.binarySearch = function(value){
       var items = this;
       console.log(items.length);
       var startIndex  = 0;
       var stopIndex = items.length - 1;
       var middle = Math.floor((stopIndex + startIndex)/2);
       while(items[middle] != value && startIndex < stopIndex){
           if (value < items[middle]){
               stopIndex = middle - 1;
   ...
   

8. binarySearchbinaryIndexOf;

   function binaryIndexOf(searchElement) {
       'use strict';
       var minIndex = 0;
       var maxIndex = this.length - 1;
       var currentIndex = -1;
       var currentElement;
       while (minIndex <= maxIndex) {
           currentIndex = (minIndex + maxIndex) / 2 | 0;
           currentElement = this[currentIndex];
   ...
   

9. binarySearchbinarySearch(val, from, to)

   Array.prototype.binarySearch = function binarySearch(val, from, to){
       if (from === undefined) {
           from = 0;
       if (to === undefined) {
           to = this.length-1;
       var mid = Math.ceil((from+to)/2),
           midVal = this[mid];
   ...