0263.go

// Source: https://leetcode.com/problems/ugly-number
// Title: Ugly Number
// Difficulty: Easy
// Author: Mu Yang <http://muyang.pro>

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// 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:
//
//   -2^31 <= n <= 2^31 - 1
//
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

package main

func isUgly(n int) bool {
	if n <= 0 {
		return false
	}

	// Divide by 2
	for n%2 == 0 {
		n /= 2
	}

	// Divide by 3
	for n%3 == 0 {
		n /= 3
	}

	// Divide by 5
	for n%5 == 0 {
		n /= 5
	}

	return n == 1
}