[Leetcode] 263. Ugly Number 解题报告

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本文介绍了一种使用C++编程语言来判断一个给定的正整数是否为丑数的方法。丑数定义为仅包含质因数2、3和5的正整数。通过不断去除给定数字中2、3和5的因子，最终检查剩余部分是否为1来完成判断。

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：

判断被2,3,5除尽之后是否等于1即可，太简单了没什么好说的。

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;
    }
};