prime-factorization | Prime Factorization

Let's say, your find_factors return all the divisor of a number. Then, you can just check the all common divisor for both x and y, and take the max that would be the divisor. Technically, you don't need the is_prime function.

For example,

If we have 12, and 4. Let's find the factors first. We will get them in a sorted manner from find_factors.

12 has factors: 1, 2, 3, 4, 6, 12

4 has factors: 1, 2, 4

possible solution set = [1, 2, 4] (the common ones only)

GCD or greatest common divisor will be only the maximum common number from both lists. So, the answer is 4.