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.
class Solution(object):
def isUgly(self, num):
"""
:type num: int
:rtype: bool
"""
if num<1:
return False
while num!=1:
if num%2==0:
num /= 2
elif num%3==0:
num /= 3
elif num%5==0:
num /= 5
else:
return False
return True
1 判断其prime factor是不是只是2，3，5中的数
2 则可以用这个数依次除以2，3，5，看最后是不是等于1
3 注意1也是丑陋数字
