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;
}
};