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Python

Keon Park
Keon Park
11,637 Points

Don't know the problem with my minimax algorithm

I am trying to write a minimax algorithm for my tictactoe game but it just returns random moves. Here is my code:

def minimax_score(board, player): # player will be X for simplicity
    original_player = player
    empty_spots = []
    other_player = None
    if player == 'X':
        other_player = 'O'
    elif player == 'O':
        other_player = 'X'

    for y in range(3): # find all open spots on board
        for x in range(3):
            if board[y][x] == None:
                empty_spots.append([y, x])

    if ttt.get_winner(board) == player:
        return 10
    elif ttt.get_winner(board) == other_player:
        return -10
    elif ttt.get_winner(board) == None and empty_spots == []:
        return 0

    scores = []
    moves = []
    for y in range(3): # find all open spots on board
        for x in range(3):
            if board[y][x] == None:
                moves.append([y, x])            
    for move in moves: # if board state is not terminal
        board[move[0]][move[1]] = player
        if player == 'X':
            player = 'O'
        elif player == 'O':
            player = 'X'
        scores.append(minimax_score(board, player))
        board[move[0]][move[1]] = None 
    player = original_player
    if player == 'X':
        return max(scores)
    elif player == 'O':
        return min(scores)


def minimax_ai(board, player):
    best_move = None
    best_score = None
    moves = []
    for y in range(3): # find all open spots on board
        for x in range(3):
            if board[y][x] == None:
               moves.append([y, x])
    for move in moves:
        new_board = copy.deepcopy(board)
        new_board[move[0]][move[1]] = player
        if player == 'X':
            player = 'O'
        elif player == 'O':
            player = 'X'
        score = minimax_score(new_board, player)
        new_board[move[0]][move[1]] = None
        if best_score is None or score > best_score:
            best_move = [move[1], move[0]]
            best_score = score

    return best_move

minimax_score gives the score for the current state of the tictactoe board. I have no clue on how to go about this problem. I apologize for how bad the code looks, I am planning on fixing it later. I wrote this without much thought since it has not been long since I started coding.

boi
boi
14,242 Points

Could you describe the working principle of your code? like, which function should be run first, and what inputs should be given to each function, what results do you get in the REPL and what are the expected results you want? Show me in code format. I'll make sure to try to solve it.