326. Power of Three

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?

不用递归和循环,这里有一个讨巧的办法,因为输入的数据是int类型,int类型最大的3的次幂是1162261467所以解决办法是:

class Solution(object):
    def isPowerOfThree(self, n):
        """
        :type n: int
        :rtype: bool
        """
        return n > 0 and 1162261467 % n == 0