leetcode 326 Power of Three (python)

原题：
Given an integer, write a function to determine if it is a power of three.

Follow up:
Could you do it without using any loop / recursion?

这个题目本身没有任何难度，也是easy等级，但是题目要求不能使用循环和迭代,解法如下：

import math
class Solution(object):
    def isPowerOfThree(self, n):
        """
        :type n: int 
        :rtype: bool
        """
        return False if n <= 0 else n == pow(3, round(math.log(n, 3)))