leetcode 231. Power of Two

Given an integer, write a function to determine if it is a power of two.

?

1 2 3 4 5 6 7 8 9 10 11

class Solution(object):     def isPowerOfTwo(self, n):         """         :type n: int         :rtype: bool         """         #-4???         if n >= 1:             return n & (n-1) == 0         else:             return False

 

?

1 2 3 4 5 6 7 8 9 10 11 12 13

class Solution(object):     def isPowerOfTwo(self, n):         """         :type n: int         :rtype: bool         """         #-4???         c = 0         while n > 0:             if n & 1:                 c += 1             n >>= 1         return c == 1