one

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

C++ 代码

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


};