Power of Three - 卖萌的弱渣

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?

Solution

Java:Find the maximum integer(1162261467) that is a power of 3 and check if it is a multiple of the given input.

(Power-of-Three.java) download

public class Solution {
    public boolean isPowerOfThree(int n) {
        return (n>0 && 1162261467 %n ==0);
    }
}

Python: 求对数，然后乘方，判断得数是否相等

(Power-of-Three.py) download

class Solution(object):
    def isPowerOfThree(self, n):
        """
        :type n: int
        :rtype: bool
        """
        return n > 0 and 3 ** (round(math.log(n,3))) == n