I have the following code, I need to finish the return statement in the findSolution method package maze;

import java.io$.$FileNotFoundException;

import java.io$.$FileReader;

import java.util.Scanner;

$/**$

$*$ MazeSolver is a backtracking version of MazeGame.

$*$

$*$ @author Mitch Parry

$*$ @author Willow Sapphire

$*$ @version $11/02/2023$

$*/$

public class MazeSolver

$\{$

$/**$

$*$ The height of game maps.

$*/$

private final static int HEIGHT $=99$;

$/**$

$*$ The width of game maps.

$*/$

private final static int WIDTH $=99$;

$/**$

$*$ The game map, as a $2$D array of booleans.

$*$ True indicates the spot is blocked.

$*/$

private boolean$[][]$ wall;

$/**$

$*$ The visited tiles on the board.

$*$ True indicates the spot has been visited.

$*/$

boolean$[][]$ visited;

$/**$

$*$ Constructor sets up the maps and the path list.

$*$

$*$ @param mazeFile name of the file containing the map.

$*/$

public MazeSolver$($String mazeFile$)$

$\{$

loadMaze$($mazeFile$)$;

$\}$

$/**$

$*$ Loads the data from the maze file and creates the map

$*2$D array.

$*$

$*$ @param mazeFile the input maze file.

$*/$

private void loadMaze$($String mazeFile$)$

$\{$

wall $=$ new boolean$[$HEIGHT$][$WIDTH$]$;

Scanner mazeScanner;

try

$\{$

mazeScanner $=$ new Scanner$($new FileReader$($mazeFile$))$;

for $($int i $=0$; i $<$ HEIGHT; i$++)$

$\{$

for $($int j $=0$; j $<$ WIDTH; j$++)$

$\{$

if $($mazeScanner$.$next$().$equals$("1"))$

$\{$

wall$[$i$][$j$]=$ true;

$\}$

$\}$

$\}$

mazeScanner.close$()$;

$\}$

catch $($FileNotFoundException e$)$

$\{$

System.out.println$("$File not found: $"+$ mazeFile$)$;

$\}$

$\}$

$/**$

$*$ Prints the map.

$*/$

public void printMap$()$

$\{$

for $($int i $=0$; i $<$ HEIGHT; i$++)$

$\{$

for $($int j $=0$; j $<$ WIDTH; j$++)$

$\{$

if $($wall$[$i$][$j$])$

$\{$

System.out.print$("$X$")$;

$\}$

else

$\{$

System.out.print$("\_")$;

$\}$

$\}$

System.out.println$()$;

$\}$

System.out.println$()$;

$\}$

private String backtrack$($int row, int col, String pathSoFar$)$

$\{$

if $($row $==$ HEIGHT $-1$ && col $==$ WIDTH $-1)$

$\{$

return pathSoFar;

$\}$

if $($row $<0||$ col $<0||$ row $>=$ HEIGHT $||$ col

$>=$ WIDTH $||$ wall$[$row$][$col$]||$ visited$[$row$][$col$])$

$\{$

return null;

$\}$

visited$[$row$][$col$]=$ true;

String$[]$ posPath $=\{"$up$",$ "down", "left", "right"$\}$;

int$[][]$ moves $=\{\{-1,0\},\{1,0\},\{0,-1\},\{0,1\}\}$;

for $($int i $=0$; i $<4$; i$++)$

$\{$

String result $=$ backtrack$($row $+$ moves$[$i$][0],$

col $+$ moves$[$i$][1],$ pathSoFar $+""+$ posPath$[$i$])$;

if $($result $!=$ null$)$

$\{$

return result;

$\}$

$\}$

visited$[$row$][$col$]=$ false;

return null;

$\}$

public String findSolution$()$

$\{$

backtrack$(0,0,"")$;

return $.$toString$()$;

$\}$

$\}$