I've noticed a lot of searches hitting my blog with my C Four program I made, here. So I'm going to go into a bit of depth about the game now. A lot of the searches say 'Program that proves Connect 4 is a draw'. This got me curious.
Wikipedia says "The game was solved mathematically by James D. Allen (Oct 1, 1988), and independently by Victor Allis (Oct 16, 1988). With perfect play, the first player can force a win by starting in the middle column. By starting in the two adjacent columns, the first player allows the second player to reach a draw; by starting with the four outer columns, the first player allows the second player to force a win."
It also has a couple links to freeware you can download that plays the perfect game. But I'd rather solve it myself.
Initial thoughts: So we know the concept, get four in a row either diagonally, horizontally or vertically. The board is 7 long and 6 high. This means that we must use the middle column to get a diagonal or horizontal win. Also a diagonal or vertical win needs the two middle rows. As the board is filled row by row, it become immediately clear that middle board dominance is essential.
Could do: I know how to model turn based games on a graph with nodes representing game state and then use logic to determine from what states a player can force a win. But that's boring and very time consuming to do by hand. See xkcd has done this for tic-tac-toe.
Will do: So what I'm going to do instead is alter my old version of C Four (get it? Connect Four but it's written in C so I called it C Four...) and create an AI that uses a depth first recursive search to find the optimum position for the next piece. I could have it build a graph at run time and then traverse the graph with each move made but computers are fast enough to handle what I'm trying to achieve here.
Basic: Make a program that looks at every possible move and picks the best one.
What I will need:
Time. I'm back from University holidays and my memory is terrible so will have to go back and learn C.
Visual Studio or something similar to develop in. I'm posting at work so will download this to my flash drive and play with the idea from there.
Money. Not for this project but it's always good to have money, am I right?
Even more lulz
Akin to my original C Four program the game is going to be in ASCII. If I am able I will keep C Four as it is and simply add the option to verse a computer player or even watch a computer player verse another computer player. This is where the money is at.
[Connect Flour image. Sorry I lost this one. But it is funny]
If it works correctly we should see the two computer players play the exact same game every time. And hopefully player 1 will always win. That would be pretty cool.
I'm going back into hospital tomorrow for my kidney stones again, but workload from University has lessened so will work on it in my downtime.