1）调库count
class Solution: def hammingWeight(self, n: int) -> int: return bin(n).count(‘1‘)
2)按位与，n&n-1等于去掉倒数的第一个1
class Solution: def hammingWeight(self, n: int) -> int: result = 0 while n: result += 1 n = n & n-1 return result
原文：https://www.cnblogs.com/cbachen/p/14874823.html