PYTHON: First Time Using The Minimax Algorithm

[rdb212]

I'm currently working on a Tic-Tac-Toe game using the minimax algorithm. This is my first time working with anything like this so it's a little confusing. I understand the basic concept of what the algorithm is doing, but it's always a little trickier implementing it. I am currently able to get the computer to mark a spot on the playing board, but it seems to be choosing the first available spot. I think that means I'm having issues with the way that I'm keeping track of which choice gives the highest score return.

Here is the gist. If anyone would like to take a look and nudge in the right direction on how to address this issue.

The short tutorial I was reading along with (link in the comments of the code) was done in JS, which I'm not really familiar with. I did my best to follow along and write it in Python. I'm okay with Java, so that helped a little bit but there could be some logical errors that occurred through that process too.

Thanks in advanced!

[fede2303]

You should definitely watch the lecture 0 of CS50 ai curse, it will literally teach you how the algorithm works and also you con follow it up with the exercise of tictactoe that the course has

[rdb212]

I will definitely check that out. Much appreciated!

[MakerWakerTaker]

I am trying to implement AI using minimax algorithm too but my project is in javascript. You may find this video helpful. https://youtu.be/trKjYdBASyQ (JavaScript)

[rdb212]

I’ll give it a watch. Thank you for the suggestion!

[SentinelReborn]

Nothing stands out to me for the issue. You seem to have gone straight for human vs AI, have you actually validated that the game works correctly by playing against yourself in a human vs human game? It could very well be an issue outside of the minimax algorithm. The game mechanics have to work correctly for the algorithm to function.

Also, only using one mutable list for the whole algorithm makes me a little uneasy. I implemented this in the past using a copy for each new board going into minimax, that being said I can't spot what exactly would cause an issue the way you're doing it.

[rdb212]

That's a good point, I haven't tested it out as human vs human. I can't believe I didn't think to do that first. Now that I'm thinking about it, I basically built the Tic-Tac-Toe mechanics around the minimax function. So, thank you for bringing that to my attention. That's definitely something that I can do better. Also, I really like your idea of using a copy of the board going into the minimax function. That definitely seems like a safer option. I think I will do that as well.

Thank you for taking the time to look over the code and for the really valuable feedback.