ゼロから始まるLCブラシ問題(64):Ugly Number

原題:
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 .
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: 14is not ugly since it includes another prime factor 7.

Note:

1  is typically treated as an ugly number.

Input is within the 32-bit signed integer range: [−231,  231 − 1].

簡単で頭がない.結果:
Success
Runtime: 0 ms, faster than 100.00% of C++ online submissions for Ugly Number.
Memory Usage: 8.1 MB, less than 47.99% of C++ online submissions for Ugly Number.
コード:

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