# -*- coding:utf-8 -*- class Solution: def NumberOf1(self, n): # write code here count = 0 c = 1 for i in range(32): p = c & n if p != 0: count += 1 c = c << 1 return count def NumberOf1_2(self, n): count=0 while n: count += 1 n = (n - 1) & n return count solution = Solution() print solution.NumberOf1_2(-2)