LeetCode OJ 之 Ugly Number （丑数）

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.

思路：

參考：http://blog.csdn.net/u012243115/article/details/45222269。

代码：

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