Leetcode 342 Power of Four

Given an integer (signed 32 bits), write a function to check whether it is a power of 4.

Example:
Given num = 16, return true. Given num = 5, return false.

Follow up: Could you solve it without loops/recursion?

满足是power of 2的条件再加上减一后能被三整除

class Solution(object):
    def isPowerOfFour(self, num):
        return num > 0 and num&(num-1) == 0 and (num-1)%3 == 0