Single Number II

public class Solution {
    public int singleNumber(int[] A) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        int len = A.length;
        if(A == null)
            return 0;
        
        int[] result = new int[32];
        int finalresult = 0;
        for(int i = 0; i < 32; i++){
            for(int j = 0; j < len; j++){
                if(((A[j] >> i) & 1) == 1)
                    result[i] = (result[i] + 1) % 3;
            }
            finalresult |= (result[i] << i);
        }
        return finalresult;
    }
}

every element appears n times except for one