leetcode 263. 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.

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