剑指 Offer 15. 二进制中1的个数

题目详细链接：https://leetcode-cn.com/problems/er-jin-zhi-zhong-1de-ge-shu-lcof/

解法1：

class Solution {
public:
    int hammingWeight(uint32_t n) {
         int cnt = 0;
         unsigned int flag = 1;
         while (flag) {
             if (flag & n) {
                 cnt++;
             }
             flag <<= 1;
         }
         return cnt;
     }
};

解法2：

class Solution {
public:
    int hammingWeight(uint32_t n) {
        int cnt =0;
        while (n) {
            cnt++;
            n = (n-1) & n;
        }
        return cnt;
    }
};