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# minimax algorithm?!?!

Greenhorn
Posts: 3
Hi all, i'm new here, i hope i posted this is the right place
...........
i am having trouble trying to apply this "minimax algorithm" thing to my basic game (its called "grundy's game") its on the web somewhere, i am just developing my own basic version.

i have googled for hours to try and find a good explanation of the minimax algorithm and/or how to apply it, but i have found nothing decent!

that is, how do you know which value to give to things and stuff like this, nowhere seems to explain this! (or is it really obvious, and so thats why they don't??)

would anyone here be able to point me in the right direction or help me out?

Thanks

sarah

Ranch Hand
Posts: 59

Originally posted by Sarah isme:
how do you know which value to give to things and stuff like this, nowhere seems to explain this!

The algorithm is a general search strategy which can be applied to different games. But the state values depend on the game, and are independent of the algorithm. You need to study the game, rather than the search algorithm. Your end result has two parts: search algorithm + state valuation algorithm.

Sarah isme
Greenhorn
Posts: 3
well the game is this game called "Grundy's Game" you can see it at
http://www.cut-the-knot.org/Curriculum/Games/Grundy.shtml

could you (If you have time) breifly explain how you use this minimax algoithm, i just don't get it at themoment

author
Marshal
Posts: 23439
138

Originally posted by Sarah isme:
could you (If you have time) breifly explain how you use this minimax algoithm, i just don't get it at themoment

The min-max algorithm is basically use play out a game. The algorithm tries to find the best next move, by playing out many moves ahead. It gets its name by how it figures it out. It tries to maximize the score when it plays its moves, and it minimizes the score when it plays the opponents. In the end it will choose the best next move by minimizing and maximizing the possible outcomes.

Of course, the minimizing part is just a guess. The opponent is under no obligation to pick the best move.

Henry

Ranch Hand
Posts: 3061
Sarah,

Welcome to Java Ranch! I hope we can help you. In fact, I've tried to post an explanation several times, but I crashed the computer the first time and the second time I closed my browser on accident.

I think there are plenty of resources on the Web that can explain it better than I can. Perhaps it will help if you tell us what you don't understand about the minimax algorithm.

Also, is this for a class in college? If so, do you have a textbook that explains the minimax algorithm? I susgest you read through it since there is probably a simple example.

One suggestion I have is to try to implement a simpler game, such as Tic-Tac-Toe using the minimax algorithm. If you can get that working, you should understand it a lot more so that you can get it working on this other game you need to do.

I hope this helps. Please answer my questions above and I will do what I can to help.

Layne

Sarah isme
Greenhorn
Posts: 3
oh ok i get it now!

thanks for all your replies everyone

i got it working! yay!

-Sarah