leetcode之Power of Four

采用的思路是求对数然后求指数的方法来验证。

import math
class Solution(object):
    def isPowerOfFour(self, num):
        """
        :type num: int
        :rtype: bool
        """
        if num <= 0:
            return False
        if 4 ** int(math.log(num, 4)) == num:
            return True
        else:
            return False