ミニマックス法の概要とアルゴリズム及び実装例について

import math

# メインの関数
def minimax(board, depth, is_maximizing):
    if board.is_winner('X'):
        return -1
    elif board.is_winner('O'):
        return 1
    elif board.is_draw():
        return 0

    if is_maximizing:
        best_score = -math.inf
        for move in board.get_available_moves():
            board.make_move(move, 'O')
            score = minimax(board, depth + 1, False)
            board.undo_move(move)
            best_score = max(score, best_score)
        return best_score
    else:
        best_score = math.inf
        for move in board.get_available_moves():
            board.make_move(move, 'X')
            score = minimax(board, depth + 1, True)
            board.undo_move(move)
            best_score = min(score, best_score)
        return best_score

# tic-tac-toeゲームのボードクラス
class TicTacToeBoard:
    def __init__(self):
        self.board = [[' ' for _ in range(3)] for _ in range(3)]

    def is_winner(self, player):
        # 勝利条件のチェック
        for i in range(3):
            if self.board[i][0] == self.board[i][1] == self.board[i][2] == player:
                return True
            if self.board[0][i] == self.board[1][i] == self.board[2][i] == player:
                return True
        if self.board[0][0] == self.board[1][1] == self.board[2][2] == player:
            return True
        if self.board[0][2] == self.board[1][1] == self.board[2][0] == player:
            return True
        return False

    def is_draw(self):
        for row in self.board:
            for cell in row:
                if cell == ' ':
                    return False
        return True

    def get_available_moves(self):
        moves = []
        for i in range(3):
            for j in range(3):
                if self.board[i][j] == ' ':
                    moves.append((i, j))
        return moves

    def make_move(self, move, player):
        self.board[move[0]][move[1]] = player

    def undo_move(self, move):
        self.board[move[0]][move[1]] = ' '

    def print_board(self):
        for row in self.board:
            print('|'.join(row))
        print('\n')

# メイン関数の実行
if __name__ == "__main__":
    board = TicTacToeBoard()
    print("Initial Board:")
    board.print_board()

    best_score = -math.inf
    best_move = None
    for move in board.get_available_moves():
        board.make_move(move, 'O')
        score = minimax(board, 0, False)
        board.undo_move(move)
        if score > best_score:
            best_score = score
            best_move = move

    print("Best move:", best_move)