Solving binary search problem from http://code-warrior.herokuapp.com.

readme.md

Binary Search

Implement a Binary search function which return the search path

Hint

Using Math.floor for calculating index to get the right path

Extra

Try to implement in recursion / iteration

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index.js

module.exports = function(array, value) {
  var left = 0;
  var right = array.length - 1;
  var tracker = [];
  while (left <= right) {
    var mid = Math.floor((left + right) / 2);
    tracker.push(array[mid]);
    if (array[mid] == value) return tracker ;
    if (array[mid] < value) {
      left = mid + 1;
    } else {
      right = mid - 1;
    };
  }
  return tracker;
}

package.json

{
  "id": 1,
  "name": "binary search",
  "level": "basic",
  "author": "Jimmy Chao"
}

test.js

var expect = require('expect.js');

var binarysearch = require('./');

describe("binary search", function() {
  var array = [1, 2, 3, 4, 5, 6];
  var array2 = [3, 6, 10, 12, 15, 20, 22, 25, 27, 29, 41, 45, 46, 58];

  it("should return search path", function() {
    expect(binarysearch(array, 3)).to.eql([3]);
    expect(binarysearch(array, 1)).to.eql([3, 1]);
    expect(binarysearch(array, 5)).to.eql([3, 5]);
    expect(binarysearch(array, 6)).to.eql([3, 5, 6]);
  });

  it("should search elements", function() {

    expect(binarysearch(array2, 29).pop()).to.equal(29);
    expect(binarysearch(array2, 15).pop()).to.equal(15);
    expect(binarysearch(array2, 7).pop()).to.not.equal(7);
  });
});