## Ugly Number

### 描述

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

Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. For example, 6, 8 are ugly while 14 is not ugly since it includes another prime factor 7.

Note that 1 is typically treated as an ugly number.

### 代码

// Ugly Number
// Time complexity: O(logn), Space complexity: O(1)
public class Solution {
public boolean isUgly(int num) {
if (num == 0) return false;
while (num % 2 == 0) num /= 2;
while (num % 3 == 0) num /= 3;
while (num % 5 == 0) num /= 5;
return num == 1;
}
}