深度优先搜索算法在迷宫中跳过空格？

问题描述

在edX上哈佛大学AI课程的第一堂课结束后，我决定实现所教授的概念，首先是深度优先搜索算法。

该程序的目的是在文本文件mazefile中输入一个迷宫，并使用深度优先搜索算法找到从S到G的路径。

该项目当前由4个文件组成，（1）具有类方法的代码来操作或使用（2）包含迷宫的文本文件，另一个包含结果文件的文本文件（3）（其中AI已探索）和主要的python脚本（4）。在这里，可以随时将它们复制并粘贴到文件夹中，并查看它们的运行方式。

processtext.py（文件1）

#code to process the mazefile file.

class importMaze:
    def __init__(self,maze):
        self.fileLines = []
        self.fileName = maze
        self.switch = False
        self.toBeReturned = []
    def processthis(self):
        f = open(self.fileName,"r")
        for x in f:
            self.fileLines.append(x[:-1])
        f.close()
        for i in self.fileLines:
            if self.switch == True:
                if str(i) == "END":
                    self.switch = False
                else:
                    self.toBeReturned.append(i)
            else:
                if str(i) == "START":
                    self.switch = True
        return self.toBeReturned
class mazePointer:
    def __init__(self,mazearray):
        self.Sample = mazearray
        self.initialPosition = []
        for y in range(0,len(self.Sample)):
           for x in range(0,len(self.Sample[y])):
               if str(self.Sample[y][x]) == "S":
                    self.initialPosition = [x,y]
        self.currentPosition = self.initialPosition
    def whatIs(self,xcoordinate,ycoordinate):
        return (self.Sample[ycoordinate])[xcoordinate]
    def nearbyFreeSpaces(self,search):
        self.freeSpaces = []
        if self.whatIs(self.currentPosition[0]-1,self.currentPosition[1]) == search:
            self.freeSpaces.append([self.currentPosition[0]-1,self.currentPosition[1]])
        if self.whatIs(self.currentPosition[0]+1,self.currentPosition[1]) == search:
            self.freeSpaces.append([self.currentPosition[0]+1,self.currentPosition[1]])
        if self.whatIs(self.currentPosition[0],self.currentPosition[1]-1) == search:
            self.freeSpaces.append([self.currentPosition[0],self.currentPosition[1]-1])
        if self.whatIs(self.currentPosition[1],self.currentPosition[1]+1) == search:
            self.freeSpaces.append([self.currentPosition[1],self.currentPosition[1]+1])
        return self.freeSpaces

    def moveto(self,position):
        self.currentPosition = position

TestingTrack.py（主文件）

from processtext import importMaze,mazePointer

testObject = importMaze("mazefile")
environment = testObject.processthis()
finger = mazePointer(environment)
frontier = []
explored = []
result = ""
def Search():
    global  result
    if len(finger.nearbyFreeSpaces("G")) == 1: #If the goal is bordering this space
        result = finger.nearbyFreeSpaces("G")[0]
        explored.append(finger.currentPosition)
    else:
        newPlaces = finger.nearbyFreeSpaces("F") #finds the free spaces bordering
        for i in newPlaces:
            if i in explored: #Skips the ones already visited
                pass
            else:
                frontier.append(i)

while result == "":
    explored.append(finger.currentPosition)
    Search()
    finger.moveto(frontier[-1])
    frontier.pop(-1)


exploredArray = []
for y in range(len(environment)): #Recreates the maze,fills in 'E' in where the AI has visited.
    holder = ""
    for x in range(len(environment[y])):
        if [x,y] in explored:
            holder+= "E"
        else:
            holder+= str(environment[y][x])
    exploredArray.append(holder)
def createResult(mazeList,title,append): #Creating the file
    file = open("resultfile",append)
    string = title + " \n F - Free \n O - Occupied \n S - Starting point \n G - Goal \n E - Explored/Visited \n (Abdulaziz Albastaki 2020) \n \n (top left coordinate - 0,0) \n "
    for i in exploredArray:
        string+= "\n" + str(i)
    string+= "\n \n Original problem \n"
    for i in environment:
        string+= "\n" +str(i)
    file.write(string)
    file.close()
def tracingPath():
    initialExplored = explored
    proceed = True
    newExplored = []
    for i in explored:
        finger.moveto() #incomplete
print(explored)
createResult(exploredArray,"DEPTH FirsT SEARCH","w")

迷宫文件（程序将读取此文件以获取迷宫）

F - Free
O - Occupied
S - Starting point
G - Goal
(Abdulaziz Albastaki 2020)

START
OOOOOOOOOOOOOOOO
OFFFFFFFFFFFFFGO
OFOOOOOOOOOOOOFO
OFOOOOOOOOOOOOFO
OFOOOOOOOOOOOOFO
OFOOOOOOOOOOOOFO
OSFFFFFFFFFFFFFO
OOOOOOOOOOOOOOOO
END



Made by Abdulaziz Albastaki in October 2020
You can change the maze and its size however it must
-Respect the key above
-Have ONE Starting point and goal
-The maze must be in between 'START' and 'END'
-The maze MUST be surrounded by occupied space


SAMPLE PROBLEMS:

OOOOOOOOOOOOOOOO
OFFFFFFFFFFFFFGO
OFOOOOOOOOOOOOFO
OFOOOOOOOOOOOOFO
OFOOOOOOOOOOOOFO
OFOOOOOOOOOOOOFO
OSFFFFFFFFFFFFFO
OOOOOOOOOOOOOOOO

OOOOOOOOOOOOOOOOO
OFOFFFFFOOOFFFOOO
OFFFOOOFOOFFOOOFO
OFOOOOOFOOFOOOOFO
OSFGFFFFFFFFFFFFO
OOOOOOOOOOOOOOOOO

还有一个结果文件，但是，如果您只创建一个具有该名称（无扩展名）的空文本文件，程序将在其中填充结果。

问题出在结果文件上，这里是：

DEPTH FirsT SEARCH 
 F - Free 
 O - Occupied 
 S - Starting point 
 G - Goal 
 E - Explored/Visited 
 (Abdulaziz Albastaki 2020) 
 
 (top left coordinate - 0,0) 
 
OOOOOOOOOOOOOOOO
OFFFFFFFFFFFFFGO
OFOOOOOOOOOOOOEO
OFOOOOOOOOOOOOEO
OFOOOOOOOOOOOOEO
OEOOOOOOOOOOOOEO
OEFFFEEEEEEEEEEO
OOOOOOOOOOOOOOOO
 
 Original problem 

OOOOOOOOOOOOOOOO
OFFFFFFFFFFFFFGO
OFOOOOOOOOOOOOFO
OFOOOOOOOOOOOOFO
OFOOOOOOOOOOOOFO
OFOOOOOOOOOOOOFO
OSFFFFFFFFFFFFFO
OOOOOOOOOOOOOOOO

AI跳过了几个空格才能达到目标，为什么这样做呢？

如有任何疑问，请随时问我。

解决方法

存在以下问题：

if中的最后一个nearbyFreeSpaces块使用了错误的索引：

if self.whatIs(self.currentPosition[1],self.currentPosition[1]+1) == search:
    self.freeSpaces.append([self.currentPosition[1],self.currentPosition[1]+1])

应为：

if self.whatIs(self.currentPosition[0],self.currentPosition[1]+1) == search:
    self.freeSpaces.append([self.currentPosition[0],self.currentPosition[1]+1])

最终位置未正确添加到路径。此块的最后一行：

if len(finger.nearbyFreeSpaces("G")) == 1: #If the goal is bordering this space
    result = finger.nearbyFreeSpaces("G")[0]
    explored.append(finger.currentPosition)

...应该是：

    explored.append(result)

algorithm algorithm artificial-intelligence depth-first-search python search