import random

​

def print_board(board):

    for row in board:

        print(" | ".join(row))

        print("-" * 9)

​

def check_winner(board, player):

    # Check rows, columns, and diagonals

    for i in range(3):

        if all(board[i][j] == player for j in range(3)) or all(board[j][i] == player for j in range(3)):

            return True

    if all(board[i][i] == player for i in range(3)) or all(board[i][2 - i] == player for i in range(3)):

        return True

    return False

​

def is_board_full(board):

    return all(cell != ' ' for row in board for cell in row)

​

def get_user_move():

    while True:

        try:

            position = int(input("Enter a number between 1 and 9: "))

            if 1 <= position <= 9:

                return position - 1

            print("Invalid input. Please enter a number between 1 and 9.")

        except ValueError:

            print("Invalid input. Please enter a number between 1 and 9.")

​

def get_user_symbol():

    while True:

        user_choice = input("Choose 'X' or 'O': ").upper()

        if user_choice in ['X', 'O']:

            return user_choice

        print("Invalid choice. Please choose 'X' or 'O.")

​

def play_game():

    user_symbol = get_user_symbol()

    computer_symbol = 'X' if user_symbol == 'O' else 'O'

    board = [[' ' for _ in range(3)] for _ in range(3)]

    players = [user_symbol, computer_symbol]

    random.shuffle(players)  # Randomize the starting player

    current_player = players[0]

​

    while True:

        print_board(board)

        position = get_user_move() if current_player == user_symbol else random.choice([(i, j) for i in range(3) for j in range(3) if board[i][j] == ' '])

        row, col = divmod(position, 3)

​

        if board[row][col] == ' ':

            board[row][col] = current_player

            if check_winner(board, current_player):

                print_board(board)

                print(f"Congratulations! {current_player} wins!")

                break

            if is_board_full(board):

                print_board(board)

                print("It's a tie!")

                break

            current_player = players[1] if current_player == players[0] else players[0]

        else:

            print("The cell is already taken. Choose another one.")

​

if __name__ == "__main__":

    play_game()