11.二进制中1的个数

class Solution {
public:
    // 1111
    // 1110 -> 1110
    //1110
    //1101 -> 1100
    // 1100
    // 1011 -> 1000
    // 1000
    // 0111 -> 0
    int NumberOf1(int n) {
        int count = 0;
        while (n) {
            count += 1;
            n = n & (n - 1);
        }
        return count;
    }
};