Minimax algorithm for connect 4

Question

I've been trying to implement minimax algorithm in connect 4 but I encountered a problem that there are only two values to evaluate moves : infinity for winning game and -infinity for the opposite , and I need a huge deep to reach these values on the first moves , so what I need is an evaluation function but I don't have any idea how should it be ... any ideas ?

score 0 · Accepted Answer · answered Dec 25 '13 at 19:26

0

First, Connect 4 also allows for a draw, so you have three possible outcomes. Second, why would you use +inf and -inf when you can use +1 and -1? Third, the obvious starting place for a board evaluation function would be "number of tokens in a line."

But that is only a starting point.

answered Dec 25 '13 at 19:26

Novak

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OK you are right but how should I evaluate neutral moves and what values can I give them if they are only between 1 and -1 – Dec 26 '13 at 21:49
You're allowed to use floats or even doubles, not just ints. Or if you really want to use ints, widen the range up a little. You're also allowed to experiment a little bit. – Novak Dec 26 '13 at 22:55

score 0 · Answer 2 · answered Dec 29 '13 at 21:50

A good Evaluation function for the game Connect Four would analyze the threats of both players. The article Expert Play in Connect-Four from James D. Allen is a great source for studying and analyzing the game. To get a clue on how to create a evaluation function read the chapter Threat Analysis carefully.

Good Luck!

Minimax algorithm for connect 4

2 Answers2