一、题目

An ugly number is a positive integer whose prime factors are limited to 2, 3, and 5.

Given an integer n, return true if n is an ugly number.

Example 1:

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

Input: n = 1
Output: true
Explanation: 1 has no prime factors, therefore all of its prime factors are limited to 2, 3, and 5.
Example 3:

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

Constraints:

-231 <= n <= 231 - 1

二、题解

class Solution {
public:bool isUgly(int n) {if(n <= 0) return false;vector<int> factors = {2,3,5};for(auto factor:factors){while(n % factor == 0) n /= factor;}return n == 1;}
};