pip install pygame

import pygame,sys,time,random
from pygame.locals import *

redColour = pygame.Color(255,0,0)
blackColour = pygame.Color(0,0,0)
whiteColour = pygame.Color(255,255,255)
greenColour = pygame.Color(0,255,0)
headColour = pygame.Color(0,119,255)

IGHT = 15
WIDTH = 15
FIELD_SIZE = HEIGHT * WIDTH
# 蛇頭位于snake數(shù)組的第一個(gè)元素
HEAD = 0

FOOD = 0
UNDEFINED = (HEIGHT + 1) * (WIDTH + 1)
SNAKE = 2 * UNDEFINED

LEFT = -1
RIGHT = 1
UP = -WIDTH # 一維數(shù)組，所以需要整個(gè)寬度都加上才能表示上下移動(dòng)。
DOWN = WIDTH 

ERR = -2333

board = [0] * FIELD_SIZE #[0,0,0,……]
snake = [0] * (FIELD_SIZE+1)
snake[HEAD] = 1*WIDTH+1
snake_size = 1

tmpboard = [0] * FIELD_SIZE
tmpsnake = [0] * (FIELD_SIZE+1)
tmpsnake[HEAD] = 1*WIDTH+1
tmpsnake_size = 1

food = 4 * WIDTH + 7
best_move = ERR

mov = [LEFT, RIGHT, UP, DOWN]
score = 1 

def is_cell_free(idx, psize, psnake):
 return not (idx in psnake[:psize]) 

def is_move_possible(idx, move):
 flag = False
 if move == LEFT:
  #因?yàn)閷?shí)際范圍是13*13,[1,13]*[1,13]，所以idx為1時(shí)不能往左跑，此時(shí)取余為1所以>1
  flag = True if idx%WIDTH > 1 else False
 elif move == RIGHT:
  #這里的<WIDTH-2跟上面是一樣的道理
  flag = True if idx%WIDTH < (WIDTH-2) else False
 elif move == UP:
  #這里向上的判斷畫(huà)圖很好理解，因?yàn)樵赱1,13]*[1,13]的實(shí)際運(yùn)動(dòng)范圍外，還有個(gè)
  #大框是圍墻，就是之前說(shuō)的那幾個(gè)行列，下面判斷向下運(yùn)動(dòng)的條件也是類似的
  flag = True if idx > (2*WIDTH-1) else False
 elif move == DOWN:
  flag = True if idx < (FIELD_SIZE-2*WIDTH) else False
 return flag

def board_reset(psnake, psize, pboard):
 for i in range(FIELD_SIZE):
  if i == food:
pboard[i] = FOOD
  elif is_cell_free(i, psize, psnake): # 該位置為空
pboard[i] = UNDEFINED
  else: # 該位置為蛇身
pboard[i] = SNAKE

def board_BFS(pfood, psnake, pboard):
 queue = []
 queue.append(pfood)
 inqueue = [0] * FIELD_SIZE
 found = False
 # while循環(huán)結(jié)束后，除了蛇的身體，
 # 其它每個(gè)方格中的數(shù)字為從它到食物的曼哈頓間距
 while len(queue)!=0: 
  idx = queue.pop(0)#初始時(shí)idx是食物的坐標(biāo) 
  if inqueue[idx] == 1: continue
  inqueue[idx] = 1
  for i in range(4):#左右上下
if is_move_possible(idx, mov[i]):
 if idx + mov[i] == psnake[HEAD]:
  found = True
 if pboard[idx+mov[i]] < SNAKE: # 如果該點(diǎn)不是蛇的身體
  if pboard[idx+mov[i]] > pboard[idx]+1:#小于的時(shí)候不管，不然會(huì)覆蓋已有的路徑數(shù)據(jù)。pboard[idx+mov[i]] = pboard[idx] + 1
  if inqueue[idx+mov[i]] == 0:queue.append(idx+mov[i])
 return found

def choose_shortest_safe_move(psnake, pboard):
 best_move = ERR
 min = SNAKE
 for i in range(4):
  if is_move_possible(psnake[HEAD], mov[i]) and pboard[psnake[HEAD]+mov[i]]<min:
 #這里判斷最小和下面的函數(shù)判斷最大，都是先賦值，再循環(huán)互相比較
min = pboard[psnake[HEAD]+mov[i]]
best_move = mov[i]
 return best_move

def is_tail_inside():
 global tmpboard, tmpsnake, food, tmpsnake_size
 tmpboard[tmpsnake[tmpsnake_size-1]] = 0 # 虛擬地將蛇尾變?yōu)槭澄?因?yàn)槭翘摂M的，所以在tmpsnake,tmpboard中進(jìn)行)
 tmpboard[food] = SNAKE # 放置食物的地方，看成蛇身
 result = board_BFS(tmpsnake[tmpsnake_size-1], tmpsnake, tmpboard) # 求得每個(gè)位置到蛇尾的路徑長(zhǎng)度
 for i in range(4): # 如果蛇頭和蛇尾緊挨著，則返回False。即不能follow_tail，追著蛇尾運(yùn)動(dòng)了
  if is_move_possible(tmpsnake[HEAD], mov[i]) and tmpsnake[HEAD]+mov[i]==tmpsnake[tmpsnake_size-1] and tmpsnake_size>3:
result = False
 return result

def follow_tail():
 global tmpboard, tmpsnake, food, tmpsnake_size
 tmpsnake_size = snake_size
 tmpsnake = snake[:]
 board_reset(tmpsnake, tmpsnake_size, tmpboard) # 重置虛擬board
 tmpboard[tmpsnake[tmpsnake_size-1]] = FOOD # 讓蛇尾成為食物
 tmpboard[food] = SNAKE # 讓食物的地方變成蛇身
 board_BFS(tmpsnake[tmpsnake_size-1], tmpsnake, tmpboard) # 求得各個(gè)位置到達(dá)蛇尾的路徑長(zhǎng)度
 tmpboard[tmpsnake[tmpsnake_size-1]] = SNAKE # 還原蛇尾
 return choose_longest_safe_move(tmpsnake, tmpboard) # 返回運(yùn)行方向(讓蛇頭運(yùn)動(dòng)1步)

def any_possible_move():
 global food , snake, snake_size, board
 best_move = ERR
 board_reset(snake, snake_size, board)
 board_BFS(food, snake, board)
 min = SNAKE
 for i in range(4):
  if is_move_possible(snake[HEAD], mov[i]) and board[snake[HEAD]+mov[i]]<min:
min = board[snake[HEAD]+mov[i]]
best_move = mov[i]
 return best_move

def shift_array(arr, size):
 for i in range(size, 0, -1):
  arr[i] = arr[i-1]
def new_food():#隨機(jī)函數(shù)生成新的食物
 global food, snake_size
 cell_free = False
 while not cell_free:
  w = random.randint(1, WIDTH-2)
  h = random.randint(1, HEIGHT-2)
  food = WIDTH*h + w
  cell_free = is_cell_free(food, snake_size, snake)
 pygame.draw.rect(playSurface,redColour,Rect(18*(food//WIDTH), 18*(food%WIDTH),18,18))

def make_move(pbest_move):
 global snake, board, snake_size, score
 shift_array(snake, snake_size)
 snake[HEAD] += pbest_move
 p = snake[HEAD]
 for body in snake:#畫(huà)蛇，身體，頭，尾
pygame.draw.rect(playSurface,whiteColour,Rect(18*(body//WIDTH), 18*(body%WIDTH),18,18))
 pygame.draw.rect(playSurface,greenColour,Rect(18*(snake[snake_size-1]//WIDTH),18*(snake[snake_size-1]%WIDTH),18,18))
 pygame.draw.rect(playSurface,headColour,Rect(18*(p//WIDTH), 18*(p%WIDTH),18,18))
 #下面一行是把初始情況會(huì)出現(xiàn)的第一個(gè)白塊bug填掉
 pygame.draw.rect(playSurface,(255,255,0),Rect(0,0,18,18))
 # 刷新pygame顯示層
 pygame.display.flip() 
 
 # 如果新加入的蛇頭就是食物的位置
 # 蛇長(zhǎng)加1，產(chǎn)生新的食物，重置board(因?yàn)樵瓉?lái)那些路徑長(zhǎng)度已經(jīng)用不上了)
 if snake[HEAD] == food:
  board[snake[HEAD]] = SNAKE # 新的蛇頭
  snake_size += 1
  score += 1
  if snake_size < FIELD_SIZE: new_food()
 else: # 如果新加入的蛇頭不是食物的位置
  board[snake[HEAD]] = SNAKE # 新的蛇頭
  board[snake[snake_size]] = UNDEFINED # 蛇尾變?yōu)閁NDEFINED，黑色
  pygame.draw.rect(playSurface,blackColour,Rect(18*(snake[snake_size]//WIDTH),18*(snake[snake_size]%WIDTH),18,18))
  # 刷新pygame顯示層
  pygame.display.flip() 

def virtual_shortest_move():
 global snake, board, snake_size, tmpsnake, tmpboard, tmpsnake_size, food
 tmpsnake_size = snake_size
 tmpsnake = snake[:] # 如果直接tmpsnake=snake，則兩者指向同一處內(nèi)存
 tmpboard = board[:] # board中已經(jīng)是各位置到達(dá)食物的路徑長(zhǎng)度了，不用再計(jì)算
 board_reset(tmpsnake, tmpsnake_size, tmpboard)
 
 food_eated = False
 while not food_eated:
  board_BFS(food, tmpsnake, tmpboard) 
  move = choose_shortest_safe_move(tmpsnake, tmpboard)
  shift_array(tmpsnake, tmpsnake_size)
  tmpsnake[HEAD] += move # 在蛇頭前加入一個(gè)新的位置
  # 如果新加入的蛇頭的位置正好是食物的位置
  # 則長(zhǎng)度加1，重置board，食物那個(gè)位置變?yōu)樯叩囊徊糠?SNAKE)
  if tmpsnake[HEAD] == food:
tmpsnake_size += 1
board_reset(tmpsnake, tmpsnake_size, tmpboard) # 虛擬運(yùn)行后，蛇在board的位置
tmpboard[food] = SNAKE
food_eated = True
  else: # 如果蛇頭不是食物的位置，則新加入的位置為蛇頭，最后一個(gè)變?yōu)榭崭?tmpboard[tmpsnake[HEAD]] = SNAKE
tmpboard[tmpsnake[tmpsnake_size]] = UNDEFINED

def find_safe_way():
 global snake, board
 safe_move = ERR
 # 虛擬地運(yùn)行一次，因?yàn)橐呀?jīng)確保蛇與食物間有路徑，所以執(zhí)行有效
 # 運(yùn)行后得到虛擬下蛇在board中的位置，即tmpboard
 virtual_shortest_move() # 該函數(shù)唯一調(diào)用處
 if is_tail_inside(): # 如果虛擬運(yùn)行后，蛇頭蛇尾間有通路，則選最短路運(yùn)行(1步)
  return choose_shortest_safe_move(snake, board)
 safe_move = follow_tail() # 否則虛擬地follow_tail 1步，如果可以做到，返回true
 return safe_move

pygame.init()

fpsClock = pygame.time.Clock()

playSurface = pygame.display.set_mode((270,270))
pygame.display.set_caption('貪吃蛇')

playSurface.fill(blackColour)

pygame.draw.rect(playSurface,redColour,Rect(18*(food//WIDTH), 18*(food%WIDTH),18,18))
while True:
 for event in pygame.event.get():#循環(huán)監(jiān)聽(tīng)鍵盤和退出事件
  if event.type == QUIT:#如果點(diǎn)了關(guān)閉
print(score)#游戲結(jié)束后打印分?jǐn)?shù)
pygame.quit()
sys.exit()
  elif event.type == KEYDOWN:#如果esc鍵被按下
if event.key==K_ESCAPE:
 print(score)#游戲結(jié)束后打印分?jǐn)?shù)
 pygame.quit()
 sys.exit()
 # 刷新pygame顯示層
 pygame.display.flip()  
 #畫(huà)圍墻，255,255,0是黃色，邊框是36是因?yàn)?，pygame矩形是以邊為初始，向四周填充邊框
 pygame.draw.rect(playSurface,(255,255,0),Rect(0,0,270,270),36)
 # 重置距離
 board_reset(snake, snake_size, board)
 # 如果蛇可以吃到食物，board_BFS返回true
 # 并且board中除了蛇身(=SNAKE)，其它的元素值表示從該點(diǎn)運(yùn)動(dòng)到食物的最短路徑長(zhǎng)
 if board_BFS(food, snake, board):
  best_move  = find_safe_way() # find_safe_way的唯一調(diào)用處
 else:
  best_move = follow_tail()
 if best_move == ERR:
  best_move = any_possible_move()
 # 上面一次思考，只得出一個(gè)方向，運(yùn)行一步
 if best_move != ERR: make_move(best_move)
 else:
  print(score)#游戲結(jié)束后打印分?jǐn)?shù)
  break
 # 控制游戲速度
 fpsClock.tick(20)#20看上去速度正好