326. Power of Three

Problem Link

Description

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Given an integer n, return true if it is a power of three. Otherwise, return false.

An integer n is a power of three, if there exists an integer x such that n == 3x.

 

Example 1:

Input: n = 27
Output: true
Explanation: 27 = 33

Example 2:

Input: n = 0
Output: false
Explanation: There is no x where 3x = 0.

Example 3:

Input: n = -1
Output: false
Explanation: There is no x where 3x = (-1).

 

Constraints:

• -231 <= n <= 231 - 1

 

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

Solution

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Python3

class Solution:
    def isPowerOfThree(self, n: int) -> bool:
        if n == 0: return False
        
        if n == 1: return True
        
        if n % 3 != 0: return False
        
        return self.isPowerOfThree(n // 3)