leetcode_263. Ugly Number 寻找丑数，即质因数只能是2，3，5的数

题目：

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.

题意：

给定一个数，判断该数是否是丑数，丑数是指质因数只能是2，3，5的数

代码：

class Solution(object):
    def isUgly(self, num):
        """
        :type num: int
        :rtype: bool
        """
        
        if num <= 0 :
            return False
        if num == 1 :
            return True
        if num%2 == 0 :
            return self.isUgly(num/2)
        if num%3 == 0 :
            return self.isUgly(num/3)
        if num%5 == 0:
            return self.isUgly(num/5)
        return False

笔记：

参考代码：http://blog.youkuaiyun.com/xudli/article/details/47786867