leetcode 191. Number of 1 Bits

191. Number of 1 Bits

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.

class Solution {
public:
    int hammingWeight(uint32_t n) {
        int num;
        for(num = 0;n;num++)
        {
            n &= n-1;//n和n-1相与，就去掉了二进制中的最右边一个1
        }
        return num;
    }
};

参考338题