263、Ugly Number

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.

解题思路：

题目比较简单。但需要考虑特殊情况。小于等于1时的情况

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