Leetcode#191. Number of 1 Bits（位运算）

声明：题目解法使用c++和Python两种，重点侧重在于解题思路和如何将c++代码转换为python代码。

题目

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.

题意

给你一个无符号的32位整数，求出它的二进制中1的个数。

解法一：C++版

强大的位运算

class Solution {
public:
int hammingWeight(uint32_t n) {
int num = 0;
while(n)
{
//& 按照位与 1 & 1 = 1 奇数 0 & 1 = 0 偶数
if(n & 1)
num++;
n = n >> 1;
}
return num;
}
};

解法二：Python版

class Solution(object):
def hammingWeight(self, n):
"""
:type n: int
:rtype: int
"""
sum = 0
while n:
if n & 1:
sum = sum + 1
n = n >> 1
return sum