[LeetCode][JavaScript]Single Number II

Single Number II

Given an array of integers, every element appears three times except for one. Find that single one.

Note:
Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory?

https://leetcode.com/problems/single-number-ii/

https://leetcode.com/discuss/857/constant-space-solution

 1 /**
 2  * @param {number[]} nums
 3  * @return {number}
 4  */
 5 var singleNumber = function(nums) {
 6     var ones = 0, twos = 0, threes = 0;
 7     for(var i = 0; i < nums.length; i++){
 8         twos |= ones & nums[i];
 9         ones ^= nums[i];
10         threes = ones & twos;
11         ones &= ~threes;
12         twos &= ~threes;
13     }
14     return ones;
15 };