leetcode刷题，总结，记录，备忘 263

leetcode263 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.

Credits:

Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases.
其实做通过之后的题目都觉得不是很难了，，一个数如果不能被2， 3， 5整除，就是ugly number，除非一直被那3个数的其中某个数，整除至1。这就是解题的中心思想，上代码。

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

最后别忘，负数和0的情况，我有几次提交没过就是因为这些。。