【发布时间】：2015-09-27 03:08:37
【问题描述】：
所以我正在编写一个生成然后解决迷宫的程序。除了这件小事，我什么都在工作。迷宫中的标记将到达完成迷宫的倒数第二个步骤，然后停止，然后移动到不同的方向。我已经为此工作了大约 2 个小时，一直在跟踪我的代码，但似乎无法找到它在最后一步中出现异常的位置或原因。
迷宫的规则是X 是墙，不能移动，O 是可以移动的可能区域，. 是起点。 - 是我已经移动到的路径。标记可以沿任何序数或基本方向（北、东北等）移动。
我有两个矩阵，一个称为mat，它使用X's 和O's 和-'s 显示给用户。我还有另一个矩阵visited，它的大小与mat 相同，是一种幕后矩阵，它跟踪我可以或不能移动到的坐标。它为墙壁存储W，为我已经访问过的坐标存储Y，为我可以访问的坐标存储N。
我解决迷宫的方法是从北开始检查可能的移动，然后围绕指南针逆时针移动，直到找到可能的移动。标记无法移动以发现它已经移动。
如果我遇到具有多个可能移动的分割路径，我将该位置的坐标放在两个堆栈中，称为 splitx 用于行，splity 用于列，以便稍后我可以回到它。如果我遇到了一个死胡同，每个方块要么是一面墙，要么已经被访问过，我会回溯到我的分割路径堆栈中的最后一个坐标，关闭我刚刚移动到的路径，然后弹出堆栈的顶部值。
我还有另一个名为visitStack 的堆栈，它将我所做的每一个动作存储为N 用于North，NE 用于Northeast，等等。这让我可以回溯我的动作并转到我遇到的最后一条分割路径。这是代码，下面是一些选择的输出。如果您对代码或输出有任何疑问，或者只是一般性的澄清，请尽管提问。
import java.util.*;
public class MazeLab
{
public static void main(String args[])
{
Scanner input = new Scanner(System.in);
System.out.print("Enter random starting seed ===>> ");
int seed = input.nextInt();
Maze maze = new Maze(seed);
maze.displayMaze();
maze.solveMaze();
}
}
class Maze
{
private char mat[][]; // 2d character array that stores the maze display
private char visited[][]; // 2d character array that works behind to scenes to let me know where I can or can't move
private Stack<String> visitStack; // stack that stores every move I make as N, NE, E, SE, etc
private int nowR, nowC; // coordinates for current position in the matrix
private int startRow, startCol; // coordinates for the starting position
private boolean done = false; // not that important
private Stack<Integer> splitx = new Stack<Integer>(); // row coord for split paths
private Stack<Integer> splity = new Stack<Integer>(); // col coord for split paths
Random random = new Random();
public Maze(int seed)
// constructor which generates the random maze, random starting location
// and initializes Maze class values. If the random value equals 0 the maze
// store an 'X' otherwise it store an 'O' in the maze.
{
Random randomize = new Random(seed);
mat = new char[12][12];
visited = new char[12][12];
for (int r = 0; r < 12; r++)
for (int c = 0; c < 12; c++)
{
if (r == 0 || c == 0 || r == 11 || c == 11)
mat[r][c] = 'X';
else
{
int rndInt = randomize.nextInt(2);
if (rndInt == 0)
mat[r][c] = 'X';
else
mat[r][c] = 'O';
}
}
mat[0][0] = 'O';
startRow = randomize.nextInt(12);
startCol = 11;
nowR = startRow;
nowC = startCol;
mat[startRow][startCol] = '.';
visitStack = new Stack<String>();
for(int i = 0; i < mat.length; i++)
for(int k = 0; k < mat[i].length; k++)
if(mat[i][k] == 'X')
visited[i][k] = 'W';
else
visited[i][k] = 'N';
// Avoid going back to the starting point
visited[nowR][nowC] = 'Y';
}
void displayMaze()
// displays the current maze configuration
{
for (int r = 0; r < 12; r++)
{
for (int c = 0; c < 12; c++)
System.out.print(mat[r][c] + " ");
System.out.println();
}
System.out.println();
if(done == false)
pause();
}
public void solveMaze()
{
// for testing purposes, this is not the real method
for(int i = 0; i < 15; i++)
{
getMove();
displayMaze();
}
}
private int numMoves()
// This method determines if a position has a valid move or not
{
int moves = 0;
if(nowR != 0 && visited[nowR-1][nowC] == 'N')
moves++;
if(nowR != 0 && nowC != 11 && visited[nowR-1][nowC+1] == 'N')
moves++;
if(nowC != 11 && visited[nowR][nowC+1] == 'N')
moves++;
if(nowR != 11 && nowC != 11 && visited[nowR+1][nowC+1] == 'N')
moves++;
if(nowR != 11 && visited[nowR+1][nowC] == 'N')
moves++;
if(nowR != 11 && nowC != 0 && visited[nowR+1][nowC-1] == 'N')
moves++;
if(nowC != 0 && visited[nowR][nowC-1] == 'N')
moves++;
if(nowR != 0 && nowC != 0 && visited[nowR-1][nowC-1] == 'N')
moves++;
return moves;
}
private void getMove()
{
if(numMoves() > 1)
{
// checks for split paths
// north
if(nowR != 0 && visited[nowR-1][nowC] == 'N')
{
splitx.push(nowR);
splity.push(nowC);
}
// northwest
if(nowR != 0 && nowC != 0 && visited[nowR-1][nowC-1] == 'N')
{
splitx.push(nowR);
splity.push(nowC);
}
// west
if(nowC != 0 && visited[nowR][nowC-1] == 'N')
{
splitx.push(nowR);
splity.push(nowC);
}
// southwest
if(nowR != 11 && nowC != 0 && visited[nowR+1][nowC-1] == 'N')
{
splitx.push(nowR);
splity.push(nowC);
}
// south
if(nowR != 11 && visited[nowR+1][nowC] == 'N')
{
splitx.push(nowR);
splity.push(nowC);
}
// southeast
if(nowR != 11 && nowC != 11 && visited[nowR+1][nowC+1] == 'N')
{
splitx.push(nowR);
splity.push(nowC);
}
// east
if(nowC != 11 && visited[nowR][nowC+1] == 'N')
{
splitx.push(nowR);
splity.push(nowC);
}
// northeast
if(nowR != 0 && nowC != 11 && visited[nowR-1][nowC+1] == 'N')
{
splitx.push(nowR);
splity.push(nowC);
}
}
if(numMoves() > 0)
{
// moves the marker, oriented to the right
// north
if(nowR != 0 && visited[nowR-1][nowC] == 'N')
{
nowR--;
visited[nowR][nowC] = 'Y';
visitStack.push("N");
mat[nowR][nowC] = '-';
// System.out.println("PUSHING ON NORTH");
}
// northwest
else if(nowR != 0 && nowC != 0 && visited[nowR-1][nowC-1] == 'N')
{
nowR--;
nowC--;
visited[nowR][nowC] = 'Y';
visitStack.push("NW");
mat[nowR][nowC] = '-';
// System.out.println("PUSHING ON NORTHWEST");
}
// west
else if(nowC != 0 && visited[nowR][nowC-1] == 'N')
{
nowC--;
visited[nowR][nowC] = 'Y';
visitStack.push("W");
mat[nowR][nowC] = '-';
// System.out.println("PUSHING ON WEST");
}
// southwest
else if(nowR != 11 && nowC != 0 && visited[nowR+1][nowC-1] == 'N')
{
nowR++;
nowC--;
visited[nowR][nowC] = 'Y';
visitStack.push("SW");
mat[nowR][nowC] = '-';
// System.out.println("PUSHING ON SOUTHWEST");
}
// south
else if(nowR != 11 && visited[nowR+1][nowC] == 'N')
{
nowR++;
visited[nowR][nowC] = 'Y';
visitStack.push("S");
mat[nowR][nowC] = '-';
// System.out.println("PUSHING ON SOUTH");
}
// southeast
else if(nowR != 11 && nowC != 11 && visited[nowR+1][nowC+1] == 'N')
{
nowR++;
nowC++;
visited[nowR][nowC] = 'Y';
visitStack.push("SE");
mat[nowR][nowC] = '-';
// System.out.println("PUSHING ON SOUTHEAST");
}
// east
else if(nowC != 11 && visited[nowR][nowC+1] == 'N')
{
nowC++;
visited[nowR][nowC] = 'Y';
visitStack.push("E");
mat[nowR][nowC] = '-';
// System.out.println("PUSHING ON EAST");
}
// northeast
else if(nowR != 0 && nowC != 11 && visited[nowR-1][nowC+1] == 'N')
{
nowR--;
nowC++;
visited[nowR][nowC] = 'Y';
visitStack.push("NE");
mat[nowR][nowC] = '-';
// System.out.println("PUSHING ON NORTHEAST");
}
}
if(numMoves() == 0)
{
while(nowR != splitx.peek() && nowC != splity.peek())
{
switch(visitStack.pop())
{
// have to backtrack the opposite direction i previously went
case "N": visited[nowR][nowC] = 'N';
mat[nowR][nowC] = 'O';
nowR++;
break;
case "NE": visited[nowR][nowC] = 'N';
mat[nowR][nowC] = 'O';
nowR++;
nowC--;
break;
case "E": visited[nowR][nowC] = 'N';
mat[nowR][nowC] = 'O';
nowC--;
break;
case "SE": visited[nowR][nowC] = 'N';
mat[nowR][nowC] = 'O';
nowR--;
nowC--;
break;
case "S": visited[nowR][nowC] = 'N';
mat[nowR][nowC] = 'O';
nowR--;
break;
case "SW": visited[nowR][nowC] = 'N';
mat[nowR][nowC] = 'O';
nowR--;
nowC++;
break;
case "W": visited[nowR][nowC] = 'N';
mat[nowR][nowC] = 'O';
nowC++;
break;
case "NW": visited[nowR][nowC] = 'N';
mat[nowR][nowC] = 'O';
nowR++;
nowC++;
break;
default: System.out.println("SOMETHING WENT WRONG WITH BACKTRACKING");
}
}
// blocks off dead ends
// north
if(nowR != 0 && visited[nowR-1][nowC] == 'N')
visited[nowR-1][nowC] = 'Y';
// northwest
else if(nowR != 0 && nowC != 0 && visited[nowR-1][nowC-1] == 'N')
visited[nowR-1][nowC-1] = 'Y';
// west
else if(nowC != 0 && visited[nowR][nowC-1] == 'N')
visited[nowR][nowC-1] = 'Y';
// southwest
else if(nowR != 11 && nowC != 0 && visited[nowR+1][nowC-1] == 'N')
visited[nowR+1][nowC-1] = 'Y';
// south
else if(nowR != 11 && visited[nowR+1][nowC] == 'N')
visited[nowR+1][nowC] = 'Y';
// southeast
else if(nowR != 11 && nowC != 11 && visited[nowR+1][nowC+1] == 'N')
visited[nowR+1][nowC+1] = 'Y';
// east
else if(nowC != 11 && visited[nowR][nowC+1] == 'N')
visited[nowR][nowC+1] = 'Y';
// northeast
else if(nowR != 0 && nowC != 11 && visited[nowR-1][nowC+1] == 'N')
visited[nowR-1][nowC+1] = 'Y';
splitx.pop();
splity.pop();
}
}
private void pause()
{
Scanner input = new Scanner(System.in);
String dummy;
System.out.print("\nPress <Enter> to continue ===>> ");
dummy = input.nextLine();
}
}
这是最后的迷宫。请注意，当标记应向西北移动以完成迷宫时，它会在下一个转弯处停留在同一位置，然后在转弯后向南移动。
【问题讨论】：
-
你有没有试过调试它，单步调试代码看看发生了什么？
-
是的，我追踪了好几次，不明白为什么它在最后一步没有向西北移动。我尝试在标记向西北移动时放置
System.out.println语句，并且它应该在最后一步移动时打印，但该位置仍然是“O” -
@Andreas i.imgur.com/4fkKYM7.png
-
@JonSnow，你做了什么？
-
使用枚举而不是硬编码字符串来检测 N,S,W,E