using minimax, implement an ai to play tic-tac-toe optimally using matlab in matlab

main.m
% Evaluation function for tic tac toe board
function score = evaluate_tictactoe(board, player)
    % check rows for victory
    score = evaluate_rows(board, player);
    % check columns for victory
    score = max(score, evaluate_cols(board, player));
    % check diagonal for victory
    score = max(score, evaluate_diag(board, player));
end

% Helper function to evaluate rows
function score = evaluate_rows(board, player)
    score = max([sum(board == player, 2); 0]);
end

% Helper function to evaluate columns
function score = evaluate_cols(board, player)
    score = max([sum(board == player, 1), 0]);
end

% Helper function to evaluate diagonal
function score = evaluate_diag(board, player)
    diag1 = board(1,1) == player && board(2,2) == player && board(3,3) == player;
    diag2 = board(1,3) == player && board(2,2) == player && board(3,1) == player;
    score = diag1 || diag2;
end

% Minimax function to choose the best move
function best_move = minimax(board, player)
    % Available moves on the board
    free_indices = find(board == 0);
    % Evaluating leaf nodes & returning leaf score
    if isempty(free_indices)
        score = evaluate_tictactoe(board, player);
        best_move = [score, -1];
        return;
    end
    % Check for victory by AI
    score = evaluate_tictactoe(board, player);
    if score > 0
        best_move = [score, -1];
        return;
    end
    % Check for victory by opponent
    other_player = 3 - player;
    score = evaluate_tictactoe(board, other_player);
    if score > 0
        best_move = [-score, -1];
        return;
    end
    % Recursively calling minimax for each available move
    minmax_scores = zeros(length(free_indices), 2);
    for i=1:length(free_indices)
        [r, c] = ind2sub(size(board), free_indices(i));
        board_copy = board; 
        board_copy(r, c) = player;
        minmax_scores(i, :) = [minimax(board_copy, other_player)(1)*-1, free_indices(i)];         
    end
    % Choosing optimal move as per current player
    if player == 1
        best_move = max(minmax_scores);
    else
        best_move = min(minmax_scores);
    end
end

% Wrapper function to use in interactive games
function board = play_tictactoe()
    board = zeros(3);
    player = 1;
    while true
        print_board(board);
        if player == 1
            % AI player's turn
            [~, move] = minimax(board, player);
            [r, c] = ind2sub(size(board), move);
            board(r, c) = player;
        else
            % Human player's turn
            [r, c] = input('player 2 move: ');
            board(r, c) = player;
        end
        score = evaluate_tictactoe(board, player);
        if score > 0
            fprintf('Player %d wins!\n', player);
            print_board(board);
            break;
        end
        if all(board(:))
            fprintf('Game over, no winner.\n');
            print_board(board);
            break;
        end
        player = 3 - player;
    end
end

% Function to print the current board configuration
function print_board(board)
    for i=1:size(board, 1)
        for j=1:size(board, 2)
            if board(i, j) == 0
                fprintf('-');
            else
                fprintf('%d', board(i, j));
            end
        end
        fprintf('\n');
    end
    fprintf('\n');
end
3322 chars
112 lines