用DFS实现AI贪吃蛇

好的，下面是一份基于深度优先搜索算法实现的AI贪吃蛇代码：

import pygame
import random

# 设置游戏场地大小
SIZE = 20
WIDTH = 800
HEIGHT = 600
ROWS = HEIGHT // SIZE
COLUMNS = WIDTH // SIZE

# 定义颜色
WHITE = (255, 255, 255)
BLACK = (0, 0, 0)
RED = (255, 0, 0)
GREEN = (0, 255, 0)
BLUE = (0, 0, 255)

# 定义方向
UP = (0, -1)
DOWN = (0, 1)
LEFT = (-1, 0)
RIGHT = (1, 0)

# 初始化pygame
pygame.init()

# 创建游戏窗口
screen = pygame.display.set_mode((WIDTH, HEIGHT))
pygame.display.set_caption('AI贪吃蛇')

# 设置游戏时钟
clock = pygame.time.Clock()


class Snake:
    def __init__(self):
        self.head = [COLUMNS // 2, ROWS // 2]
        self.body = [self.head, [self.head[0], self.head[1] + 1], [self.head[0], self.head[1] + 2]]
        self.direction = UP
        self.score = 0

    def move(self, apple):
        # 判断新的蛇头位置是否合法
        new_head = [self.head[0] + self.direction[0], self.head[1] + self.direction[1]]
        if new_head[0] < 0 or new_head[0] >= COLUMNS or new_head[1] < 0 or new_head[1] >= ROWS or new_head in self.body:
            return False

        self.head = new_head
        self.body.insert(0, self.head)

        # 如果吃到苹果，增加分数并生成新的苹果
        if self.head == apple:
            self.score += 1
            return True
        else:
            self.body.pop()
            return False


class Apple:
    def __init__(self):
        self.position = [random.randint(0, COLUMNS - 1), random.randint(0, ROWS - 1)]

    def draw(self):
        pygame.draw.rect(screen, RED, (self.position[0] * SIZE, self.position[1] * SIZE, SIZE, SIZE))


def dfs(snake, apple, visited):
    # 如果找到苹果，返回路径
    if snake.head == apple.position:
        return []

    # 遍历所有可能的方向
    for direction in [UP, DOWN, LEFT, RIGHT]:
        new_head = [snake.head[0] + direction[0], snake.head[1] + direction[1]]
        if new_head[0] < 0 or new_head[0] >= COLUMNS or new_head[1] < 0 or new_head[1] >= ROWS or new_head in snake.body or new_head in visited:
            continue

        # 尝试以该方向继续搜索
        new_snake = Snake()
        new_snake.head = new_head
        new_snake.body = [new_head] + snake.body[:-1]
        new_snake.direction = direction
        visited.append(new_head)
        path = dfs(new_snake, apple, visited)

        # 如果找到了一条路径，返回路径
        if path is not None:
            return [new_head] + path

    # 没有找到路径，返回空
    return None


def update_screen(snake, apple):
    # 绘制背景
    screen.fill(BLACK)

    # 绘制苹果和蛇
    apple.draw()
    for body_part in snake.body:
        pygame.draw.rect(screen, GREEN, (body_part[0] * SIZE, body_part[1] * SIZE, SIZE, SIZE))

    # 绘制分数
    font = pygame.font.SysFont('arial', 30)
    text = font.render('Score: ' + str(snake.score), True, WHITE)
    screen.blit(text, (10, 10))

    # 更新屏幕
    pygame.display.update()


def main():
    snake = Snake()
    apple = Apple()

    while True:
        # 处理事件
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
                quit()

        # 计算下一步方向
        visited = []
        path = dfs(snake, apple, visited)
        if path is not None:
            next_direction = [path[0][0] - snake.head[0], path[0][1] - snake.head[1]]
            snake.direction = next_direction

        # 移动蛇
        if not snake.move(apple.position):
            break

        # 生成新的苹果
        apple = Apple()

        # 更新屏幕
        update_screen(snake, apple)

        # 设置游戏时钟
        clock.tick(10)

    # 显示游戏结束信息
    font = pygame.font.SysFont('arial', 50)
    text = font.render('Game Over!', True, WHITE)
    screen.blit(text, (WIDTH // 2 - text.get_width() // 2, HEIGHT // 2 - text.get_height() // 2))
    pygame.display.update()
    pygame.time.wait(2000)

    # 退出游戏
    pygame.quit()
    quit()


if __name__ == '__main__':
    main()

该代码使用深度优先搜索算法计算下一步的方向，以使蛇能够吃到苹果。搜索过程中，如果找到了一条路径，就返回该路径，并将蛇的方向设置为该路径的第一个方向。如果找不到路径，就继续尝试其他方向，直到所有方向都尝试完毕。