class Solution {
public:
    int NumberOf1(int n) {
        int count = 0;
        for(int i = 0; i < 32; ++i)
            if(n >> i & 1) count++;
        return count;
    }
};


class Solution {
public:
    int NumberOf1(int n) {
        int count = 0;
        while(n) n -= n & -n, count++;
        return count;
    }
};