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ugly_number.py
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ugly_number.py
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# An ugly number is a positive integer whose prime factors are limited to 2, 3, and 5.
# Given an integer n, return true if n is an ugly number.
# Example 1:
# Input: n = 6
# Output: true
# Explanation: 6 = 2 × 3
# Example 2:
# Input: n = 1
# Output: true
# Explanation: 1 has no prime factors, therefore all of its prime factors are limited to 2, 3, and 5.
# Example 3:
# Input: n = 14
# Output: false
# Explanation: 14 is not ugly since it includes the prime factor 7.
# Constraints:
# -231 <= n <= 231 - 1
# I will iterate through specified primes and divide n by each prime in desc order and check,
# if after all divisions it will == 1
class Solution:
def isUgly(self, n: int) -> bool:
valid_primes = [5, 3, 2]
if n <= 0:
return False
for prime in valid_primes:
while n % prime == 0:
n /= prime
return n == 1