Power of Three — LeetCode 326 Python Solution

The problem

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

Example

Input

n = 27

Output

true

Explanation

27 = 33

Python solution

class Solution:
    def isPowerOfThree(self, n: int) -> bool:
        while n > 2:
            if n % 3:
                return False
            n //= 3
        return n == 1

Complexity

Pattern: Math and Number Theory

Find the closed form, the invariant, or the modular identity — and skip the loop entirely. LeetCode 326. Power of Three is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Math.

The math and number theory guide has the Python template for the pattern and the 485 LeetCode problems that use it.

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