leetcode:191. number of 1 bits

题目描述

Write a function that takes an unsigned integer and return the number of ‘1’ bits it has (also known as the Hamming weight).

Example 1:

1
2
3
Input: 00000000000000000000000000001011
Output: 3
Explanation: The input binary string 00000000000000000000000000001011 has a total of three '1' bits.

Example 2:

1
2
3
Input: 00000000000000000000000010000000
Output: 1
Explanation: The input binary string 00000000000000000000000010000000 has a total of one '1' bit.

Example 3:

1
2
3
Input: 11111111111111111111111111111101
Output: 31
Explanation: The input binary string 11111111111111111111111111111101 has a total of thirty one '1' bits.

代码实现

1
2
3
4
5
6
7
8
9
10
11
12
13
class  {
public:
int hammingWeight(uint32_t n) {
int result = 0;
while (n > 0){
if (n & 1) {
result ++;
}
n >>= 1;
}
return result;
}
};