2_8.py

"""
Mini-max Tic-Tac-Toe Player
"""

import poc_ttt_gui
import poc_ttt_provided as provided

# Set timeout, as mini-max can take a long time
import codeskulptor
codeskulptor.set_timeout(60)

# SCORING VALUES - DO NOT MODIFY
SCORES = {provided.PLAYERX: 1,
          provided.DRAW: 0,
          provided.PLAYERO: -1}

LOOKUP = {}

def mm_move(board, player):
    """
    Make a move on the board.
    
    Returns a tuple with two elements.  The first element is the score
    of the given board and the second element is the desired move as a
    tuple, (row, col).
    """
    winner = board.check_win()
    if winner != None:
        return SCORES[winner], (-1, -1)
    else:
        if player == provided.PLAYERX:
            best_score = float("-inf")
        elif player == provided.PLAYERO:
            best_score = float("inf")
        best_move =  (-1, -1)
        
        for move in board.get_empty_squares():
            clone = board.clone()
            clone.move(move[0], move[1], player)
            
            if clone.__str__() in LOOKUP:
                values = LOOKUP[clone.__str__()]
            else:
                # Call function recursively 
                values = mm_move(clone, provided.switch_player(player))
                LOOKUP[clone.__str__()] = values[0], move
       
           
            if SCORES[player] == values[0]:
                return values[0], move

            if values[0] * SCORES[player] > best_score * SCORES[player]:
                best_score = values[0]
                best_move = move
        return best_score, best_move 

def move_wrapper(board, player, trials):
    """
    Wrapper to allow the use of the same infrastructure that was used
    for Monte Carlo Tic-Tac-Toe.
    """
    move = mm_move(board, player)
    assert move[1] != (-1, -1), "returned illegal move (-1, -1)"
    return move[1]

# provided.play_game(move_wrapper, 1, False)        
poc_ttt_gui.run_gui(3, provided.PLAYERO, move_wrapper, 1, False)