題目：

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.
Example 1:

Input: 6 
Output: true 
Explanation: 6 = 2 × 3 

Example 2:

Input: 8 
Output: true 
Explanation: 8 = 2 × 2 × 2

Example 3:

Input: 14 
Output: false  
Explanation: 14 is not ugly since it includes another prime factor 7. 

Note:
1 is typically treated as an ugly number. Input is within the 32-bit signed integer range: [−231, 231 − 1].

解釋：
判斷一個數是不是醜數，醜數的定義是隻能被2,3,5整除的正整數，1是醜數。
對這個數進行判斷沒如果能被2,3,5整除，就除以這些數字，如果不能被這些數中的任意一個整除，就返回false。
python程式碼：

class Solution(object):
    def isUgly(self, num):
        """
        :type num: int
        :rtype: bool
        """
        if num<=0:
            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 

c++程式碼：

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

總結：
沒啥好說的。