Reference no: EM13162885

modifying the program so that it can start from a user-defined starting position (other than 0,0) and search for a user defined ending point (other than row-1, column-1) .

import java.util.*;
import java.io.*;

public class Maze
{
    private static final int TRIED = 2;
    private static final int PATH = 3;


    private int [][] grid = { {1,1,1,0,1,1,0,0,0,1,1,1,1},
            {1,0,0,1,1,0,1,1,1,1,0,0,1},
            {1,1,1,1,1,0,1,0,1,0,1,0,0},
            {0,0,0,0,1,1,1,0,1,0,1,1,1},
            {1,1,1,0,1,1,1,0,1,0,1,1,1},
            {1,0,1,0,0,0,0,1,1,1,0,0,1},
            {1,0,1,1,1,1,1,1,0,1,1,1,1},
            {1,0,0,0,0,0,0,0,0,0,0,0,0},
            {1,1,1,1,1,1,1,1,1,1,1,1,1} };
  
   

    /**
     * Marks the specified position in the maze as TRIED
     *
     * @param row the index of the row to try
     * @param col the index of the column to try
     */
    public void tryPosition(int row, int col)
    {
        grid[row][col] = TRIED;
    }
   
    /**
     * Return the number of rows in this maze
     *
     * @return the number of rows in this maze
     */
    public int getRows()
    {
        return grid.length;
    }
   
    /**
     * Return the number of columns in this maze
     *
     * @return the number of columns in this maze
     */
    public int getColumns()
    {
        return grid[0].length;
    }

    /**
     * Marks a given position in the maze as part of the PATH
     *
     * @param row the index of the row to mark as part of the PATH
     * @param col the index of the column to mark as part of the PATH
     */
    public void markPath(int row, int col)
    {
        grid[row][col] = PATH;
    }

    /**
     * Determines if a specific location is valid. A valid location
     * is one that is on the grid, is not blocked, and has not been TRIED.
     *
     * @param row the row to be checked
     * @param column the column to be checked
     * @return true if the location is valid   
     */
    public boolean validPosition(int row, int column)
    {
        boolean result = false;

        // check if cell is in the bounds of the matrix
        if (row >= 0 && row < grid.length &&
            column >= 0 && column < grid[row].length)

            // check if cell is not blocked and not previously tried
            if (grid[row][column] == 1)
                result = true;

        return result;
    }

    /**
     * Returns the maze as a string.
     *
     * @return a string representation of the maze
     */
    public String toString()
    {
        String result = "\n";

        for (int row=0; row < grid.length; row++)
        {
            for (int column=0; column < grid[row].length; column++)
                result += grid[row][column] + "";
            result += "\n";
        }

        return result;
    }
private Maze maze;
   
    /**
     * Constructor for the MazeSolver class.
     * @return
     */
    public void MazeSearch(Maze maze)
    {
        this.maze = maze;
    }

public boolean traverse()
{
    boolean done = false;
    int row, column;
    Position pos = new Position();
    Deque<Position> stack = new LinkedList<Position>();
    stack.push(pos);
   
    while (!(done) && !stack.isEmpty())
    {
        pos = stack.pop();
        maze.tryPosition(pos.getx(),pos.gety()); // this cell has been tried
        if ((pos).GetX() == maze.getRows()-1 && pos.gety() == maze.getColumns()-1)
            done = true; // the maze is solved
        else
        {
            push_new_pos(pos.getx() - 1,pos.gety(), stack);
            push_new_pos(pos.getx() + 1,pos.gety(), stack);
            push_new_pos(pos.getx(),pos.gety() - 1, stack);
            push_new_pos(pos.getx(),pos.gety() + 1, stack);
        }
        if (done)
            maze.markPath(pos.getx(),pos.gety());
    }
   
    return done;
}
private void push_new_pos(int x, int y,
        Deque<Position> stack)
{
Position npos = new Position();
npos.setx(x);
npos.sety(y);
if (maze.validPosition(x,y))
stack.push(npos);
}
}