请帮我编写一个HEX棋程序，并实现人机对战

好的，HEX棋是一种两人对弈的棋类游戏，目标是通过连接自己的两个边来构建一个无间断的路径，阻止对手连接自己的两个边。接下来我会为您介绍如何编写一个HEX棋程序，并实现人机对战。

1. 定义游戏规则和棋盘

首先，我们需要定义游戏规则和棋盘。HEX棋是一个 $n \times n$ 的正六边形棋盘，每个正六边形有六个相邻的正六边形。为了方便计算，我们可以使用二维数组来表示棋盘。

class HexBoard:
    def __init__(self, board_size):
        self.board_size = board_size
        self.board = [['.' for _ in range(board_size)] for _ in range(board_size)]

    def is_valid_move(self, move):
        return 0 <= move[0] < self.board_size and 0 <= move[1] < self.board_size and self.board[move[0]][move[1]] == '.'

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

    def is_game_over(self):
        # TODO: 判断游戏是否结束
        pass

    def print_board(self):
        for i in range(self.board_size):
            print(' ' * i, end='')
            for j in range(self.board_size):
                print(self.board[i][j], end=' ')
            print()

2. 实现人机对战

接下来，我们需要实现人机对战。我们可以使用博弈树来搜索最佳的下一步棋。在搜索过程中，我们需要考虑两个方面：1）如何评估当前棋局的价值；2）如何选择最佳的下一步棋。

class HexPlayer:
    def __init__(self, player, board):
        self.player = player
        self.board = board

    def get_move(self):
        # TODO: 实现博弈树搜索算法，返回最佳下一步棋
        pass

    def alpha_beta_search(self, depth, alpha, beta, player):
        if depth == 0 or self.board.is_game_over():
            return self.evaluate_board()

        if player == self.player:
            max_val = float('-inf')
            for move in self.get_valid_moves():
                self.board.make_move(move, player)
                val = self.alpha_beta_search(depth - 1, alpha, beta, self.get_opponent(player))
                self.board.make_move(move, '.')
                max_val = max(max_val, val)
                alpha = max(alpha, val)
                if beta <= alpha:
                    break
            return max_val
        else:
            min_val = float('inf')
            for move in self.get_valid_moves():
                self.board.make_move(move, player)
                val = self.alpha_beta_search(depth - 1, alpha, beta, self.get_opponent(player))
                self.board.make_move(move, '.')
                min_val = min(min_val, val)
                beta = min(beta, val)
                if beta <= alpha:
                    break
            return min_val

    def evaluate_board(self):
        # TODO: 实现评估函数，返回当前棋局的价值
        pass

    def get_valid_moves(self):
        # TODO: 返回当前可用的下一步棋
        pass

    def get_opponent(self, player):
        return 'O' if player == 'X' else 'X'

3. 完成游戏循环

最后，我们需要完成游戏循环，让玩家和AI轮流下棋，直到游戏结束。在每一轮中，我们需要打印当前棋盘，并提示玩家下一步棋。如果玩家输入的不是合法的下一步棋，则需要重新提示玩家输入。

def play_game():
    board_size = 11
    board = HexBoard(board_size)
    players = {'X': HexPlayer('X', board), 'O': HumanPlayer('O', board)}
    current_player = 'X'
    while not board.is_game_over():
        board.print_board()
        move = players[current_player].get_move()
        if board.is_valid_move(move):
            board.make_move(move, current_player)
            current_player = players[current_player].get_opponent(current_player)
        else:
            print('Invalid move, please try again.')

    board.print_board()
    print('Game over.')
    winner = board.get_winner()
    if winner:
        print(f'{winner} wins!')
    else:
        print('It\'s a tie.')

完整代码如下：