15算法课程 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.

Credits:
Special thanks to @ts for adding this problem and creating all test cases.

solution:

按位与计算1的个数

code:

class Solution {public:    int hammingWeight(uint32_t n) {        unsigned int cnt = 0;        for(int i = 0; i< 32; i++)        {            cnt += (n&1==1)?1:0;            n = n>>1;        }        return cnt;    }};