## 263. Ugly Number

Write a program to check whether a given number is an ugly number.

Ugly numbers are positive numbers whose prime factors only include `2, 3, 5`.

Example 1:

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

Example 2:

```Input: 8
Output: true
Explanation: 8 = 2 × 2 × 2
```

Example 3:

```Input: 14
Output: false
Explanation: `14` is not ugly since it includes another prime factor `7`.
```

Note:

1. `1` is typically treated as an ugly number.
2. Input is within the 32-bit signed integer range: [−231,  231 − 1].

## Rust Solution

``````struct Solution;

impl Solution {
fn is_ugly(mut num: i32) -> bool {
if num < 1 {
return false;
}
while num % 2 == 0 {
num /= 2;
}
while num % 3 == 0 {
num /= 3;
}
while num % 5 == 0 {
num /= 5;
}
num == 1
}
}

#[test]
fn test() {
assert_eq!(Solution::is_ugly(6), true);
assert_eq!(Solution::is_ugly(8), true);
assert_eq!(Solution::is_ugly(14), false);
}
``````

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