# 263. Ugly Number

## Description

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

## Solutions

Keep being devided by these prime numbers, if the remaining number is 1, it is an ugly number.

• class Solution {
public boolean isUgly(int n) {
if (n < 1) return false;
while (n % 2 == 0) {
n /= 2;
}
while (n % 3 == 0) {
n /= 3;
}
while (n % 5 == 0) {
n /= 5;
}
return n == 1;
}
}

• class Solution {
public:
bool isUgly(int n) {
if (n < 1) return false;
while (n % 2 == 0) {
n /= 2;
}
while (n % 3 == 0) {
n /= 3;
}
while (n % 5 == 0) {
n /= 5;
}
return n == 1;
}
};

• 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


• func isUgly(n int) bool {
if n < 1 {
return false
}
for _, x := range []int{2, 3, 5} {
for n%x == 0 {
n /= x
}
}
return n == 1
}

• /**
* @param {number} n
* @return {boolean}
*/
var isUgly = function (n) {
if (n < 1) return false;
while (n % 2 === 0) {
n /= 2;
}
while (n % 3 === 0) {
n /= 3;
}
while (n % 5 === 0) {
n /= 5;
}
return n === 1;
};


• class Solution {
/**
* @param Integer $n * @return Boolean */ function isUgly($n) {
while ($n) { if ($n % 2 == 0) {
$n =$n / 2;
} elseif ($n % 3 == 0) {$n = $n / 3; } elseif ($n % 5 == 0) {
$n =$n / 5;
} else {
break;
}
}
return \$n == 1;
}
}