[Mod edit: Please avoid posting codes on the forum.]
This is the solution, but I can’t understand how it works 
If you don’t understand any published solution, please quote the author’s name and the programming language instead of posting a solution when you ask here. Or you may ask your question in the comment area of that solution.
What author ? I found a solution on github. One cannot access solution in codingame unless one has a solution. So only way to get to a solution is to find it one the web 
Oops, I assumed you were asking about a published solution on CodinGame…
Then that’s more reason for you not to post a Github solution here…
I was asking for some council. Cause I am really stuck with this combinatorics thing.
You may send me the link in private message. I’ll try to see if I can understand that solution and maybe explain it to you.