Four-in-a-row (FlashPascal program)

[SilverWarior]

Is it just my opinion or you also did some work on AI making it smarter?

[Roland Chastain]

Is it just my opinion or you also did some work on AI making it smarter?

Indeed, I remade the AI. I hope I made it better.

The evaluation procedure is more precise. I use an array of all good sequences. Each sequence found increase the result.

const  motifs: array[0..13, 0..1]of string = (
    ('OOOO', 'XXXX'),
    ('OOO.', 'XXX.'),
    ('.OOO', '.XXX'),
    ('OO.O', 'XX.X'),
    ('O.OO', 'X.XX'),
    ('OO..', 'XX..'),
    ('O.O.', 'X.X.'),
    ('O..O', 'X..X'),
    ('.O.O', '.X.X'),
    ('..OO', '..XX'),
    ('O...', 'X...'),
    ('.O..', '.X..'),
    ('..O.', '..X.'),
    ('...O', '...X')
  );


const
  demiDroites: array[0..24, 0..3] of integer = (
    (1, 1, +1,  0),
    (1, 2, +1,  0),
    (1, 3, +1,  0),
    (1, 4, +1,  0),
    (1, 5, +1,  0),
    (1, 6, +1,  0),
    (1, 1,  0, +1),
    (2, 1,  0, +1),
    (3, 1,  0, +1),
    (4, 1,  0, +1),
    (5, 1,  0, +1),
    (6, 1,  0, +1),
    (7, 1,  0, +1),
    (1, 1, +1, +1),
    (1, 2, +1, +1),
    (1, 3, +1, +1),
    (1, 4, +1, -1),
    (1, 5, +1, -1),
    (1, 6, +1, -1),
    (7, 1, -1, +1),
    (7, 2, -1, +1),
    (7, 3, -1, +1),
    (7, 4, -1, -1),
    (7, 5, -1, -1),
    (7, 6, -1, -1)
  );


function tClasseGrille.Points(const aPion: char): integer;
var
  i, j, k, l: integer;
  x, y: integer;
  segment: string;
begin
  result := 0;
  l := Ord(aPion = BLANC);
  
  for i := Low(demiDroites) to High(demiDroites) do
  begin
    x := demiDroites[i, 0];
    y := demiDroites[i, 1];
    
    segment := '       ';
    
    j := 1;
    repeat
      segment[j] := grille[x, y];
      Inc(x, demiDroites[i, 2]);
      Inc(y, demiDroites[i, 3]);
      Inc(j);
    until (x < UN) or (x > SEPT) or (y < UN) or (y > SIX);
    
    for j := Low(motifs) to High(motifs) do
      if Pos(motifs[j, l], segment) > 0 then
      begin
        case j of
          0:
            k := 75000;
          1..4:
            k := 2500;
          5..9:
            k := 50;
          else
            k := 1;
        end;
        Inc(result, k);
      end;
  end;
end;

[SilverWarior]

Indeed, I remade the AI. I hope I made it better.

It made it much harder. So far after about a dozen plays I haven't won even once. Lost two times and the rest times resulted in draw.
But now the AI moves seems ... artificial. When you are playing AI doesen't just prevent you from winning but on my opinion prevent you even from coming close to winning.
In all my lays I havent managed to reach a point where I would have tre in a row and AI would be forced to block the fourth one. AI simply folows certain path were it even prevents you to prepare any posible winning situation. And this is a joy killer.

[Roland Chastain]

AI simply follows certain path were it even prevents you to prepare any posible winning situation.

Yes, it's a very good observation.

    if Max(a) >= 2500 then
      result := IndexOf(a, Min(a))

The a variable is an array of the maximal opponent's score at next move. And 2500 means three stones aligned.

And this is a joy killer.

Yes, I see what you mean. I will keep it in mind. Anyway thank you for trying my program and for your instructive report.

[SilverWarior]

All you have to do is add some randomization into your AI calculations which would alow it to make some unsafe move every now and then. This would make AI moves to feel omre human.

If you need someone to playtest and analyze your game I'm usually up for it. You would be surprised how much I have learned this way.

[Dan]

hasn't been able to beat me even once, so still needs more improvement

[Roland Chastain]

All you have to do is add some randomization into your AI calculations which would alow it to make some unsafe move every now and then. This would make AI moves to feel more human.

If you need someone to playtest and analyze your game I'm usually up for it. You would be surprised how much I have learned this way.

Thank you for your suggestion and for your willingness to help.

hasn't been able to beat me even once, so still needs more improvement

Thank you for testing. I hope I will improve it soon.

Happy Easter!

[Roland Chastain]

I made a quick modification inspired by SilverWarior's suggestion.

I hope the code is clearer than my explanation would be.

    aux := Max(a);
    
    //if Max(a) >= BONUS[3] then

    if (aux >= BONUS[4]) or (aux >= BONUS[3]) and (RandomAB(1, 2) < 2) then
      result := IndexOf(a, Min(a))

And here is an example of a bad move than the previous formula used to avoid : DDCC (computer plays black).