Jan 12 - Ugly Number; Math; Digits; Primes;

代码：

public class Solution {
    public boolean isUgly(int num) {
        if(num == 0) return false;
        //if(num == 1 || num == 2 || num == 3 || num == 5) return true;
        //if(num % 2 != 0 && num % 3 != 0 && num % 5 != 0) return false;
        while(num % 2 == 0) num = num/2;
        while(num % 3 == 0) num = num/3;
        while(num % 5 == 0) num = num/5;
        if(num == 1) return true;
        else return false;
    }
}