<![CDATA[//**************************** Maze.java ******************************
import java.io.*;
class MazeCell {
int x, y;
MazeCell() {
}
MazeCell(int i, int j) {
x = i; y = j;
}
boolean equals(MazeCell cell) {
return x == cell.x && y == cell.y;
}
}
class Maze {
int rows = 0, cols = 0;
char[][] store;
MazeCell currentCell, exitCell = new MazeCell(), entryCell = new MazeCell();
final char exitMarker = 'e', entryMarker = 'm', visited = '.';
final char passage = '0', wall = '1';
Stack mazeStack = new Stack();
Maze() {
int row = 0, col = 0;
Stack mazeRows = new Stack();
InputStreamReader isr = new InputStreamReader(System.in);
BufferedReader buffer = new BufferedReader(isr);
String str;
System.out.println("Enter a rectangular maze using the following "
+ "characters:\nm - entry\ne - exit\n1 - wall\n0 - passage\n"
+ "Enter one line at at time; end with Ctrl-z (PC) or Ctrl-D (Unix):");
try {
str = buffer.readLine();
while (str != null) {
row++;
cols = str.length();
str = "1" + str + "1"; // put 1s in the borderline cells;
mazeRows.push(str);
if (str.indexOf(exitMarker) != -1) {
exitCell.x = row;
exitCell.y = str.indexOf(exitMarker);
}
if (str.indexOf(entryMarker) != -1) {
entryCell.x = row;
entryCell.y = str.indexOf(entryMarker);
}
str = buffer.readLine();
}
} catch(IOException eof) {
}
rows = row;
store = new char[rows+2][]; // create a 1D array of char arrays;
store[0] = new char[cols+2]; // a borderline row;
for ( ; !mazeRows.isEmpty(); row--)
store[row] = ((String) mazeRows.pop()).toCharArray();
store[rows+1] = new char[cols+2]; // another borderline row;
for (col = 0; col <= cols+1; col++) {
store[0][col] = wall; // fill the borderline rows with 1s;
store[rows+1][col] = wall;
}
}
void display(PrintStream out) {
for (int row = 0; row <= rows+1; row++)
out.println(store[row]);
out.println();
}
void pushUnvisited(int row, int col) {
if (store[row][col] == passage || store[row][col] == exitMarker)
mazeStack.push(new MazeCell(row,col));
}
void exitMaze(PrintStream out) {
int row = 0, col = 0;
currentCell = entryCell;
out.println();
while (!currentCell.equals(exitCell)) {
row = currentCell.x;
col = currentCell.y;
display(System.out); // print a snapshot;
if (!currentCell.equals(entryCell))
store[row][col] = visited;
pushUnvisited(row-1,col);
pushUnvisited(row+1,col);
pushUnvisited(row,col-1);
pushUnvisited(row,col+1);
if (mazeStack.isEmpty()) {
display(out);
out.println("Failure");
return;
}
else currentCell = (MazeCell) mazeStack.pop();
}
display(out);
out.println("Success");
}
static public void main (String args[]) {
(new Maze()).exitMaze(System.out);
}
}
]]>