# Ugly Number Problem

## Description

LeetCode Problem 263.

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:

``````1
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Input: n = 6
Output: true
Explanation: 6 = 2 &times; 3
``````

Example 2:

``````1
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Input: n = 8
Output: true
Explanation: 8 = 2 &times; 2 &times; 2
``````

Example 3:

``````1
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Input: n = 14
Output: false
Explanation: 14 is not ugly since it includes the prime factor 7.
``````

Example 4:

``````1
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Input: n = 1
Output: true
Explanation: 1 has no prime factors, therefore all of its prime factors are limited to 2, 3, and 5.
``````

Constraints:

• -2^31 <= n <= 2^31 - 1

## Sample C++ Code

``````1
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class Solution {
public:
bool isUgly(int num) {
if (num == 1)
return true;
if (num <= 0)
return false;
while (num > 1) {
if (num % 2 == 0)
num /= 2;
else if (num % 3 == 0)
num /= 3;
else if (num % 5 == 0)
num /= 5;
else
return false;
}
return true;
}
};
``````