コード例 #1
0
        private MinMaxScore MinMaxPlay(Board board, int depth, Play play)
        {
            Board newBoard = new Board(board);

            if (play != null)
            {
                // make move.
                newBoard.MarkBoard(play);

                // see if play results in final state.
                MinMaxScore minMaxScore = GetMinMaxScore(newBoard, play, depth);

                // if so, return score.
                if (minMaxScore != null)
                {
                    return(minMaxScore);
                }
            }

            // update marker type.
            Marker marker = play == null
                ? Marker.O : (play.PlayerId == Marker.O)
                ? Marker.X : Marker.O;

            depth++;

            List <Play> possiblePlays = PossiblePlaysInCurrentBoardState(newBoard, marker);
            // Compute every possible move's score and add to list
            List <MinMaxScore> moves = possiblePlays.Select(possibleMove => MinMaxPlay(newBoard, depth, possibleMove)).ToList();

            // Find maximum score on list.
            MinMaxScore maxMinMaxScoreMove = FindMaxScore(moves);

            return(maxMinMaxScoreMove);
        }
コード例 #2
0
        private MinMaxScore GetMinMaxScore(Board board, Play play, int depth)
        {
            MinMaxScore minMaxScore = new MinMaxScore
            {
                Play   = play,
                Points = 0
            };

            // Check win condition for player X
            if (board.IsVictoryCondition(Marker.X))
            {
                minMaxScore.Points = play.PlayerId == Marker.X ? 10 - depth : depth - 10;
                return(minMaxScore);
            }
            // Check win condition for player O
            if (board.IsVictoryCondition(Marker.O))
            {
                minMaxScore.Points = play.PlayerId == Marker.O ? 10 - depth : depth - 10;
                return(minMaxScore);
            }
            // Check draw condition
            if (board.AreAllPositionMarked())
            {
                return(minMaxScore);
            }
            // otherwise...
            return(null);
        }
コード例 #3
0
        private Play DecidePlay(Board board)
        {
            // Ground Rule #1: start marking center position.
            int center = (board.Size - 1) / 2;

            if (board.GetMarkAtPosition(center, center) == Marker.Empty)
            {
                return(PlayAtCenter(center));
            }
            // Ground Rule #2: if center's already marked and board's only marked once, mark a corner.
            if (board.GetTotalMarks() == 1)
            {
                return(PlayAtAnyCorner(board));
            }
            // Generic move.
            MinMaxScore maximumScore = MinMaxPlay(board, 0, null);

            return(maximumScore.Play);
        }