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?

 

public class Solution {
    public int singleNumber(int[] nums) {
        int[] arr = new int[32];
        int res = 0;
        for (int i = 0; i < 32; i++) {
        	for (int j = 0; j < nums.length; j++) {
        		if (((nums[j]>>i) & 1) != 0) {
        			arr[i] = (arr[i]+1)%3;
        		}
        	}
        	res |= arr[i]<<i;
        }
        return res;
    }
}