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.

Note that 1 is typically treated as an ugly number.

分别于2，3，5取余，然后取整，如果最终的结果为1，说明为ugly number;否则返回false。代码如下：

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;
        if(num == 1) return true;
        return false;
    }
}