LeetCode:Ugly Number

问题描述：

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：
注意考虑循环退出条件以及边界条件。

代码：

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