Ugly Number Python Solution with Tests

Tested Python solution for LeetCode 263 with 20 pytest cases. Generate a practice environment with lcpy.

LeetCode 263, Easy. Topics: Math. View on LeetCode.

Generate this problem as a practice environment: tested reference solution, 20 parametrized pytest cases, and a playground notebook:

lcpy gen -n 263   # by problem number
lcpy gen -s ugly_number   # by problem name

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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.

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Examples

Input: n = 6
Output: true
Explanation: 6 = 2 × 3

Input: n = 1
Output: true
Explanation: 1 has no prime factors.

Input: n = 14
Output: false
Explanation: 14 is not ugly since it includes the prime factor 7.

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Constraints

• -2^31 <= n <= 2^31 - 1

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Solution

Reference implementation from solution.py on GitHub, full suite in test_solution.py:

class Solution:
    # Time: O(log n)
    # Space: O(1)
    def is_ugly(self, n: int) -> bool:
        if n <= 0:
            return False
        for p in (2, 3, 5):
            while n % p == 0:
                n //= p
        return n == 1

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Complexity

Time	Space
O(log n)	O(1)

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Tags

NeetCode All.