LeetCode 137. Single Number II

public class Solution {    public int singleNumber(int[] nums) {        int r = 0;        for (int i = 0; i < 32; i++) {        int bit = 1 << i;        int sum = 0;        for (int j = 0; j < nums.length; j++) {        if ((nums[j] & bit) != 0) sum++;        }        if ((sum % 3) != 0) r += bit;        }        return r;    }}