LeetCode -- Ugly Number

题目描述：




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.


判断一个数是否为ugly number。


对2,3,5执行以下过程：
不断除n，直到无法整除。


最后剩余数字为1，则该数为ugly number。






实现代码：

public class Solution {    public bool IsUgly(int num)     {        if(num <= 0){            return false;        }        num = Divide(num,2);    num = Divide(num,3);    num = Divide(num,5);        return num == 1;    }private int Divide(int num, int a){while(num % a == 0){num /= a;}return num;}}