【leetcode 简单】 第八十题 3的幂

class Solution:
    def isPowerOfThree(self, n):
        """
        :type n: int
        :rtype: bool
        """
 #       if n == 0 : return False
 #       elif n == 1 : return True
 #       elif (n%3==0):return self.isPowerOfThree(n/3)
 #       else: return False
        if n < 1:
            return False
        
        while (n % 3) == 0:
            n //= 3
            
        return n == 1