How to rate a connect four game situation in java

Question

I am trying to write a simple AI for a "Get four" game. The basic game principles are done, so I can throw in coins of different color, and they stack on each other and fill a 2D Array and so on and so forth. until now this is what the method looks like:

public int insert(int x, int color)  //0 = empty, 1=player1 2=player2"

X is the horizontal coordinate, as the y coordinate is determined by how many stones are in the array already, I think the idea is obvious.

Now the problem is I have to rate specific game situations, so find how many new pairs, triplets and possible 4 in a row I can get in a specific situation to then give each situation a specific value. With these values I can setup a "Game tree" to then decide which move would be best next (later on implementing Alpha-Beta-Pruning). My current problem is that I can't think of an efficient way to implement a rating of the current game situation in a java method.
Any ideas would be greatly appreciated!

Answer 1

I'm guessing that this is a homework assignment, and that you mean you want to write the evaluation function and don't know what tricks to use?

The game is called "Connect 4" in English, so you can google for "connect 4 evaluation function".

You can find enough people discussion heuristics.

Please don't copy an actual source code, it's an important exercise :)

Answer 2

The search space for Connect 4 isn't impossibly large. For a simple implementation, albeit one that'll take a while to run (perhaps tens of minutes) do a minimax search until someone wins, or the game ends. Assign +1 or -1 for a win for one player or the other, and 0 for a draw.

Answer 3

bollocks. search space is huge. you need to use a predefined table if you want to do that.