461. Hamming Distance

time: O(k), k is the length of binary string of x^y

space: O(1)

class Solution {
    public int hammingDistance(int x, int y) {
        int n = x^y;
        int count = 0;
        while (n != 0) {
            count++;
            n &= (n-1);
        }
        return count;
    }
}