[LeetCode] 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.

只能想到最简单的方法。

 1 class Solution {
 2 public:
 3     int hammingWeight(uint32_t n) {
 4         int res = 0;
 5         while (n) {
 6             res += (n & 1);
 7             n >>= 1;
 8         }
 9         return res;
10     }
11 };