[LeetCode]Number of 1 Bits

Posted 2020-07-01 skycore

题目描述:

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.

解题思路:

注意是无符号整形。

 1 class Solution {
 2 public:
 3     int hammingWeight(uint32_t n) {
 4         int count = 0;
 5         while (true) {
 6             if (n == 0) break;
 7             if (n == 1) {
 8                 ++count;
 9                 break;
10             }
11             
12             if (n & 1 != 0) {
13                 ++count;
14             }
15             n >>= 1;
16         }
17         
18         return count;
19     }
20 };