191Number 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.

第一种思路 类似十进制转二进制

class Solution {public:    int hammingWeight(uint32_t n) {         int sum = 0; while(n) { if(n%2 == 1)sum++; n /= 2; } return sum;    }};

第二种  直接进行为运算。。。

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