Ugly Number — LeetCode 263 Python Solution

The problem

An ugly number is a positive integer which does not have a prime factor other than 2, 3, and 5. Given an integer n, return true if n is an ugly number.

Example

Input

n = 6

Output

true

Explanation

6 = 2 × 3

Python solution

class Solution:
    def isUgly(self, n: int) -> bool:
        if n < 1:
            return False
        for x in [2, 3, 5]:
            while n % x == 0:
                n //= x
        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 263. Ugly Number 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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