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.

解题思路：

根据题目的描述一个数是Ugly number需要满足如下两个条件之一：

（1）num=1

（2）num=2^i*3^j*5^k

AC代码如下：

class Solution{
public:
	bool isUgly(int num){
		if (num <= 0) return false;
		if (num == 1) return true;
		while (num>1){
			if (num % 5 == 0){
				num = num / 5;
			}
			else if (num % 3 == 0){
				num = num / 3;
			}
			else if (num % 2 == 0){
				num = num / 2;
			}
			else{
				return false;
			}
		}
		return true;
	}
};