LeetCode: 191. Number of 1 Bits

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).

Example 1:

Input: 11
Output: 3
Explanation: Integer 11 has binary representation 00000000000000000000000000001011

Example 2:

Input: 128
Output: 1
Explanation: Integer 128 has binary representation 00000000000000000000000010000000

解题思路

直接按位统计 1 的个数。

AC 代码

class Solution {
public:
    int hammingWeight(uint32_t n) {
        int cnt = 0;

        while(n)
        {
            cnt += (n&1);
            n = n >> 1;
        }

        return cnt;
    }
};