LeetCode之191 Number of 1 Bits 别名：数1

题很简单，原题如下：

Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as the Hamming weight).

For example, the 32-bit integer ’11' has binary representation 00000000000000000000000000001011, so the function should return 3.

依然是按位与

代码如下：

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