[LeetCode]263. Ugly Number ★

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本文链接： https://blog.csdn.net/xingyu97/article/details/100095558

题目描述

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.
题目大意：判断一个数是否是丑数，丑数的定义就是一个只包含2、3或5的公约数的正数（1属于丑数）

样例

Example 1:

Input: 6
Output: true
Explanation: 6 = 2 × 3

Example 2:

Input: 8
Output: true
Explanation: 8 = 2 × 2 × 2

Example 3:

Input: 14
Output: false
Explanation: 14 is not ugly since it includes another prime factor 7.

python解法

class Solution:
    def isUgly(self, num: int) -> bool:
        if num<1:return False
        while not num % 2: num = num // 2
        while not num % 3: num = num // 3
        while not num % 5: num = num // 5
        return True if num == 1 else False

Runtime: 40 ms, faster than 55.74% of Python3 online submissions for Ugly Number.
Memory Usage: 13.9 MB, less than 6.67% of Python3 online submissions for Ugly Number.
题后反思：无

C语言解法

bool isUgly(int num){
    bool flag = true;
    if (num < 1)
        return false;
    while(true)
    {
        flag = true;
        if (num % 2 == 0)
        {
            num /= 2;
            flag = false;
        }
        if (num % 3 == 0)
        {
            num/=3;
            flag = false;
        }
        if (num % 5 == 0)
        {
            num /= 5;
            flag = false;
        }
        if (num == 1)
            return true;
        if (flag)
            break;
    }
    return false;
}

Runtime: 0 ms, faster than 100.00% of C online submissions for Ugly Number.
Memory Usage: 6.6 MB, less than 100.00% of C online submissions for Ugly Number.
题后反思：

文中都是我个人的理解，如有错误的地方欢迎下方评论告诉我，我及时更正，大家共同进步