Python写一份用极大极小值搜索实现三子棋人机对弈的代码

好的，以下是一个用极大极小值搜索实现三子棋人机对弈的 Python 代码示例：

import math

# 定义棋盘大小
BOARD_SIZE = 3

# 定义棋盘状态
EMPTY = '-'
AI_PLAYER = 'O'
HUMAN_PLAYER = 'X'

# 极大极小值搜索算法
def minimax(board, depth, player):
    if check_win(board, AI_PLAYER):
        return 10 - depth
    elif check_win(board, HUMAN_PLAYER):
        return depth - 10
    elif check_draw(board):
        return 0

    if player == AI_PLAYER:
        best_score = -math.inf
        for move in get_possible_moves(board):
            new_board = make_move(board, move, player)
            score = minimax(new_board, depth + 1, HUMAN_PLAYER)
            best_score = max(best_score, score)
        return best_score
    else:
        best_score = math.inf
        for move in get_possible_moves(board):
            new_board = make_move(board, move, player)
            score = minimax(new_board, depth + 1, AI_PLAYER)
            best_score = min(best_score, score)
        return best_score

# 获取可行的落子位置
def get_possible_moves(board):
    moves = []
    for i in range(BOARD_SIZE):
        for j in range(BOARD_SIZE):
            if board[i][j] == EMPTY:
                moves.append((i, j))
    return moves

# 落子
def make_move(board, move, player):
    x, y = move
    new_board = [row[:] for row in board]
    new_board[x][y] = player
    return new_board

# 检查是否胜利
def check_win(board, player):
    for i in range(BOARD_SIZE):
        if all(board[i][j] == player for j in range(BOARD_SIZE)):
            return True
        if all(board[j][i] == player for j in range(BOARD_SIZE)):
            return True
    if all(board[i][i] == player for i in range(BOARD_SIZE)):
        return True
    if all(board[i][BOARD_SIZE - i - 1] == player for i in range(BOARD_SIZE)):
        return True
    return False

# 检查是否平局
def check_draw(board):
    for i in range(BOARD_SIZE):
        for j in range(BOARD_SIZE):
            if board[i][j] == EMPTY:
                return False
    return True

# 人机对弈
def play():
    board = [[EMPTY] * BOARD_SIZE for _ in range(BOARD_SIZE)]
    while True:
        print_board(board)
        if check_win(board, AI_PLAYER):
            print("You lose!")
            break
        elif check_win(board, HUMAN_PLAYER):
            print("You win!")
            break
        elif check_draw(board):
            print("Draw!")
            break

        # AI 落子
        best_score = -math.inf
        best_move = None
        for move in get_possible_moves(board):
            new_board = make_move(board, move, AI_PLAYER)
            score = minimax(new_board, 0, HUMAN_PLAYER)
            if score > best_score:
                best_score = score
                best_move = move
        board = make_move(board, best_move, AI_PLAYER)

        print_board(board)
        if check_win(board, AI_PLAYER):
            print("You lose!")
            break
        elif check_win(board, HUMAN_PLAYER):
            print("You win!")
            break
        elif check_draw(board):
            print("Draw!")
            break

        # 人类落子
        while True:
            row = int(input("Enter row (1-3): ")) - 1
            col = int(input("Enter column (1-3): ")) - 1
            if board[row][col] == EMPTY:
                board[row][col] = HUMAN_PLAYER
                break

# 打印棋盘
def print_board(board):
    print("   1 2 3")
    for i in range(BOARD_SIZE):
        row = str(i + 1) + " "
        for j in range(BOARD_SIZE):
            row += board[i][j] + " "
        print(row)

# 开始游戏
play()

这个代码实现了一个简单的三子棋人机对弈，使用了极大极小值搜索算法来计算 AI 落子的最佳位置。您可以尝试运行代码进行游戏，也可以根据自己的需求进行修改和扩展。