tic-tac-toe using minimax algorithm only one player in matlab

main.m
function [score] = evaluate(board)
    % Evaluate the board and return a score.
    % +10 if computer wins, -10 if human wins, 0 if tie.
    if check_win(board, 'O')
        score = 10;
        return;
    elseif check_win(board, 'X')
        score = -10;
        return;
    elseif all(all(board ~= ' '))
        score = 0;
        return;
    end
    score = 0;
end

function [winner] = check_win(board, player)
    % Check if the given player has won.
    % Return true if so, false otherwise.
    winner = false;
   
    for i = 1:3
        if board(i, :) == repmat(player, 1, 3) || ...
           board(:, i) == repmat(player, 3, 1) || ...
           all(diag(board) == repmat(player, 3, 1)) || ...
           all(diag(fliplr(board)) == repmat(player, 3, 1))
            winner = true;
            break;
        end
    end
end

function [score, move] = minimax(board, depth, is_max)
    % Apply the Minimax Algorithm to the board and return the best move.
    % Depth is the number of moves ahead to consider, and is_max is true if
    % it's the computer's turn.
    if check_win(board, 'O')
        score = 10;
        return;
    elseif check_win(board, 'X')
        score = -10;
        return;
    elseif all(all(board ~= ' '))
        score = 0;
        return;
    end
    
    if is_max
        best_score = -Inf;
        move = struct('x', 0, 'y', 0);
        for i = 1:3
            for j = 1:3
                if board(i, j) == ' '
                    board(i, j) = 'O';
                    [score, ~] = minimax(board, depth+1, false);
                    board(i, j) = ' ';
                    if score > best_score
                        best_score = score;
                        move.x = i;
                        move.y = j;
                    end
                end
            end
        end
        score = best_score;
    else
        best_score = Inf;
        for i = 1:3
            for j = 1:3
                if board(i, j) == ' '
                    board(i, j) = 'X';
                    [score, ~] = minimax(board, depth+1, true);
                    board(i, j) = ' ';
                    if score < best_score
                        best_score = score;
                    end
                end
            end
        end
        score = best_score;
    end
end

board = repmat(' ', 3, 3);

while true
    % User's turn
    disp(board);
    x = input('Enter row (1-3): ');
    y = input('Enter column (1-3): ');
    board(x, y) = 'X';
    if check_win(board, 'X')
        disp(board);
        disp('You win!');
        break;
    elseif all(all(board ~= ' '))
        disp(board);
        disp('Tie!');
        break;
    end
    
    % Computer's turn
    [~, move] = minimax(board, 0, true);
    board(move.x, move.y) = 'O';
    if check_win(board, 'O')
        disp(board);
        disp('You lose!');
        break;
    elseif all(all(board ~= ' '))
        disp(board);
        disp('Tie!');
        break;
    end
end
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