137. Single-Number-II

/**
 * @param {number[]} nums
 * @return {number}
 */
var singleNumber = function(nums) {
    let res = 0;
    for(let i = 0; i < 32; i++){
        let digit = 0;
        for(let num of nums){
            digit += (num >> i) & 1;
        }
        digit = digit % 3;
        res = res | (digit << i);
    }
    return res;
};