Nodejs Array Search Binary binarySearch(value)

Method Source Code

Array.prototype.binarySearch = function(value){
    var items = this;
    console.log(items.length);/*  w w w . ja v a 2s .c o m*/
    var startIndex  = 0;
    var stopIndex = items.length - 1;
    var middle = Math.floor((stopIndex + startIndex)/2);

    while(items[middle] != value && startIndex < stopIndex){

        //adjust search area
        if (value < items[middle]){
            stopIndex = middle - 1;
        } 
        if (value > items[middle]){
            startIndex = middle + 1;
        }

        //recalculate middle
        middle = Math.floor((stopIndex + startIndex)/2);
    }

    //make sure it's the right value
    return (items[middle] != value) ? console.log(-1) : console.log(middle);
}

sam = [6,7,8,5,3, 4, 2,9,1]
sam.binarySearch(7);

Related

1. 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);
   ...
   

2. 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];
   ...
   

3. 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) {
   ...
   

4. binarySearch(val)

   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;
   ...
   

5. binarySearch(value)

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

6. 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];
   ...
   

7. 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];
   ...
   

8. binary_search(val, left, right)

   Array.prototype.binary_search = function(val, left, right) {
       if (typeof left === 'undefined') left = 0;
       if (typeof right === 'undefined') right = this.length - 1;
       if (left > right) return null;
       var mid = (left + right) >> 1;
       if (val == this[mid]) {
           return mid;
       } else if (val > this[mid]) {
           return this.binary_search(val, mid + 1, right);
   ...
   

9. binarysearch(i)

   Array.prototype.binarysearch = function (i) {
       var l = 0, u = this.length,  m;
       while ( l <= u ) {
           m = ((l+u) >> 1);
           if ( i > this[m].i ) {
               l = m+1;
           } else {
               u = (i == this[m]) ? -2 : m - 1;
       return (u == -2) ? m : -1;
   };