README.md

326. Power of Three

Given an integer, write a function to determine if it is a power of three.

Example 1:

Input: 27
Output: true

Example 2:

Input: 0
Output: false

Example 3:

Input: 9
Output: true

Example 4:

Input: 45
Output: false

Follow up:

Could you do it without using any loop / recursion?

Solutions (Python)

1. Iteration

class Solution:
    def isPowerOfThree(self, n: int) -> bool:
        while n % 3 == 0 and n != 0:
            n //= 3

        return n == 1

2. Mathematical

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

3. Integer Limitations

class Solution:
    def isPowerOfThree(self, n: int) -> bool:
        return n > 0 and 1162261467 % n == 0