number of 1 bits

题目地址：https://leetcode.com/problems/number-of-1-bits/

解答：

public class Solution {
    // you need to treat n as an unsigned value
    public int hammingWeight(int n) {
        int count = 0;
        while(n!=0){
            count++;
            n&=(n-1);
        }
        return count;
    }
}