leetcode Question: Ugly Number

Ugly Number

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.

Analysis:

The easiest but may be not very optimal solution is just divide the test case by 2, 3, and 5. Finally, the ugly number would return a "1".

Code(C++):

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

Code(Python):

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