lintcode-easy-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. For example, 6, 8 are ugly while 14 is not ugly since it includes another prime factor 7.

 

Notice

Note that 1 is typically treated as an ugly number.

Example

Given num = 8 return true
Given num = 14 return false

 

public class Solution {
    /**
     * @param num an integer
     * @return true if num is an ugly number or false
     */
    public boolean isUgly(int num) {
        // Write your code here
        if(num <= 0)
            return false;
        
        if(num == 1)
            return true;
        
        while(num % 2 == 0)
            num /= 2;
        
        while(num % 3 == 0)
            num /= 3;
        
        while(num % 5 == 0)
            num /= 5;
        
        return num == 1;
    }
}