python：迷宫生成，搜索（广度优先），图形界面演示搜索过程

和之前八皇后问题用一样的框架：

所谓迷宫，结构上就是一棵树，没有环路，生成的方法，就是随机在图形中找一点，然后它有四个方向可以发展，这四个点加入step1_nodes，然后再把step1_nodes设回step0_nodes，再次产生候选节点，这样的话，发展节点就呈现以开始节点为中心以菱形向四周扩展的形态。那么就不是迷宫了，实际从起始点有四个候选点，他随机发展一个，以后的发展都是从step0_nodes中选取一个，发展出来的节点加入step0_nodes，当一个节点四周都是已经发展的节点了，那么这个节点就从step0_nodes删除，最后图形中找不到一个可以发展的点，所有step0_nodes的节点也被删除了，结构上就是一棵树，也就是迷宫，设定一个起点，一个终点。

查找就简单了，就是从出发点发展，这次不是造迷宫，可以用菱形扩散法，也就是广度优先。

图形演示，和八皇后一样框架，这个程序的话，其中下面两句尤为重要，因为真的是画了很多线，虽然都很短，画完后，保存到图像，以后直接作为背景使用：

            select_rect = CMG.screen.subsurface(0,0,800,570)
            CMG.back_ground = select_rect.copy()

import pygame
import sys
import os
import random
import time
from pygame.locals import *
import tkinter as tk
from tkinter import *
import tkinter.messagebox  # 要使用messagebox先要导入模块

class Maze:
    size = None
    print_str=(('##','  '),('#',' '))
    map = None
    direct = ((-2,0),(2,0),(0,2),(0,-2),(-2,0),(2,0),(0,2))

    @staticmethod
    def check_move(map,yx):
        for d in range(0,4):
            if(map[yx[0]+Maze.direct[d][0]][yx[1]+Maze.direct[d][1]] == 0):
                return True
        return False
    @staticmethod
    def create_maze(size_para):
        WAY = 1
        size=[size_para[0]*2+3,size_para[1]*2+3]
        Maze.size = size
        direct = Maze.direct
        center=[random.randint(1,size[0]-1)//2*2,random.randint(1,size[1]-1)//2*2]
        map= [[100]*size[1] for i in range(size[0])]
        for y in range(size_para[0]):
            for x in range(size_para[1]):
                map[2*y+2][2*x+2] = 0
        step0_nodes = [center]
        map[center[0]][center[1]] = WAY
        step1_nodes = []

        while len(step0_nodes) > 0:
            node_no = random.randint(0,len(step0_nodes)-1)
            yx= step0_nodes[node_no]
            if not Maze.check_move(map,yx):
                step0_nodes.pop(node_no)
                continue
            direct_start = random.randint(0,3)
            for d in range(direct_start,direct_start+4):
                y=yx[0]+direct[d][0]
                x=yx[1]+direct[d][1]
                if(map[y][x] == 0):
                    step1_nodes.append((y,x))
                    map[yx[0]+direct[d][0]//2][yx[1]+direct[d][1]//2] = WAY
                    map[y][x] = WAY
                    break
            step0_nodes.extend(step1_nodes)
            step1_nodes.clear()
        Maze.map = map

    @staticmethod
    def solve_maze(startY,endYX):
        WAY = 1
        direct = Maze.direct
        center=(startY*2+2,2,-1)
        map = Maze.map
        steps_nodes = []
        step0_nodes = [center]
        map[center[0]][center[1]] = 0
        step1_nodes = []

        while len(step0_nodes) > 0:
            steps_nodes.append(step0_nodes)
            for n in range(0,len(step0_nodes)):
                yx= step0_nodes[n]
                for d in range(0,4):
                    y=yx[0]+direct[d][0]
                    x=yx[1]+direct[d][1]
                    y3=yx[0]+direct[d][0]//2
                    x3=yx[1]+direct[d][1]//2
                    if(map[y3][x3] != 100 and map[y][x] == WAY ):
                        step1_nodes.append((y,x,n))
                        map[yx[0]+direct[d][0]][yx[1]+direct[d][1]] = 0
                        if y == endYX[0]*2 and x== endYX[1]*2:
                            steps_nodes.append(step1_nodes)
                            return steps_nodes
            step0_nodes = step1_nodes[:]
            step1_nodes.clear()
        return None

class CMG: #画面显示管理
    screen = None
    map = None
    gameAnswer = None
    WHITE = (255, 255, 255)
    GREEN = (0, 255, 0)
    RED = (255, 0, 0)
    BLUE = (0, 0, 255)
    blocksize = 0
    step = 0
    back_ground = None

    def __init__(self,screen,map,gameAnswer):
        if CMG.screen == None:
            #print("#############OS.PATH=%s"% os.path.dirname(os.path.abspath(__file__)))
            CMG.screen = screen
            CMG.map = map
            CMG.gameAnswer = gameAnswer
            if 800//len(map[0]) > 570//len(map):
                CMG.blocksize = 570//len(map)
            else:
                CMG.blocksize = 800//len(map[0])
        #如果存在对象成员
        self.init_game_info()

    def init_game_info(self):
        pass

    def printAll(self):
        if CMG.step > len(CMG.gameAnswer):
            return
        CMG.screen.fill((0, 0, 0))
        size = Maze.size
        if CMG.back_ground == None:
            for y in range(1,size[0]-1):
                for x in range(1,size[1]-1):
                    val = CMG.map[y][x]
                    if y%2==1 and x%2==0 and val == 100:
                        #start_pos = [(y*CMG.blocksize,x*CMG.blocksize)]
                        end_pos = [((x-1)*CMG.blocksize,y*CMG.blocksize),((x+1)*CMG.blocksize,y*CMG.blocksize)]
                        pygame.draw.lines(CMG.screen, CMG.GREEN,0 , end_pos, 2)
                    elif y%2==0 and x%2==1 and val == 100:
                        end_pos = [(x*CMG.blocksize,(y-1)*CMG.blocksize),(x*CMG.blocksize,(y+1)*CMG.blocksize)]
                        pygame.draw.lines(CMG.screen, CMG.GREEN,0 , end_pos, 2)
            select_rect = CMG.screen.subsurface(0,0,800,570)
            CMG.back_ground = select_rect.copy()
        else:
            self.screen.blit(CMG.back_ground,(0,0))
        if CMG.step == len(CMG.gameAnswer):
            step = CMG.step - 1
            step_node = CMG.gameAnswer[step]
            yx = step_node[len(step_node)-1]
            while(yx[2]!=-1):
                y = yx[0]
                x = yx[1]
                step -= 1
                step_node = CMG.gameAnswer[step]
                yx = step_node[yx[2]]
                pygame.draw.rect(CMG.screen, CMG.WHITE, (((x-1)*CMG.blocksize+2,(y-1)*CMG.blocksize+2), (CMG.blocksize*2-4, CMG.blocksize*2-4)), 0)
        else:
            step_node = CMG.gameAnswer[CMG.step]
            for s in range(0,len(step_node)):
                yx = step_node[s]
                y = yx[0]
                x = yx[1]
                #pygame.draw.rect(background, (0, 255, 0), ((200, 5), (100, 100)), 3)
                pygame.draw.rect(CMG.screen, CMG.WHITE, (((x-1)*CMG.blocksize+2,(y-1)*CMG.blocksize+2), (CMG.blocksize*2-4, CMG.blocksize*2-4)), 0)

        CMG.step += 1

    def moveAll(self):
        pass

#------------------------------------------------
#tkinter,pygame混合区 START
#------------------------------------------------
root = tk.Tk()
root.resizable(0,0)

embed = tk.Frame(root, width = 800, height = 570) #creates embed frame for pygame window
embed.grid(columnspan = (800), rowspan = 730) # Adds grid
embed.pack(side = TOP) #packs window to the left

buttonwin = tk.Frame(root, width = 800, height = 150)
buttonwin.pack(side = BOTTOM)

os.environ['SDL_WINDOWID'] = str(embed.winfo_id())
os.environ['SDL_VIDEODRIVER'] = 'windib'

screen = pygame.display.set_mode((800,570))

#pygame.init()
pygame.display.init()
pygame.mixer.init()
#------------------------------------------------
#tkinter,pygame混合区 END
#------------------------------------------------

#参数，因为函数内要使用之外的变量，需要globe，因此全部打包
class PARAM:
    STATUS = 0
    TICK_NORMAL = 5

#按钮动作区 =====================================
def exit_game():
    global param
    param.STATUS = 100
#控件定义区 =====================================
button_exit_b = Button(buttonwin,text = '退出画面', width=7, command=exit_game)
button_exit_b.place(x=740,y=100)


#状态，参数，循环中使用，比如STATUS=0:初次进入，1:...100:退出
param = PARAM()
Maze.create_maze([30,50])
steps_nodes = Maze.solve_maze(0,(25,49))
param.cmg = CMG(screen,Maze.map,steps_nodes)
#------------------------------------------------
#主函数，使用pygame框架，无限LOOP对各种事件然后相应处理
#------------------------------------------------
def main():
    global param
    #pygame.mixer.music.play(-1)
    clock = pygame.time.Clock()

    while True:
        #这段event代码是必须的，哪怕在这个程序中不需要，不执行的话整个框架转不动
        for event in pygame.event.get():
            if event.type == QUIT:
                sys.exit()

        #画面按钮按下后，修改param.STATUS,实际动作这里实现
        if  param.STATUS == 100:
            #退出按钮
            if tk.messagebox.askokcancel('提示', '要退出画面吗'):
                break
            param.STATUS = 0
        elif param.STATUS == 10:
            pass
            
        param.cmg.printAll()

        #显示游戏画面
        pygame.display.flip()
        #设置帧率：长期画面不操作，设置成最闲
        clock.tick(param.TICK_NORMAL)
            
        root.update()

main()