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.

Credits:
Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases.

代码如下：

public class Solution {

    public boolean isUgly(int num) {

        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;

    }

}

　　运行结果：