package backtracking;

import java.util.Scanner;

/*You are given a N*N maze with a rat placed at maze[0][0]. Find whether any path exist that rat can follow to reach its destination i.e. maze[N-1][N-1]. Rat can move in any direction ( left, right, up and down).

Value of every cell in the maze can either be 0 or 1. Cells with value 0 are blocked means rat cannot enter into those cells and those with value 1 are open.

Input Format

Line 1: Integer N

Next N Lines: Each line will contain ith row elements (separated by space)

Output Format :

The output line contains true if any path exists for the rat to reach its destination otherwise print false.

Sample Input 1 :

3

1 0 1

1 0 1

1 1 1

Sample Output 1 :

true

Sample Input 2 :

3

1 0 1

1 0 1

0 1 1

Sample Output 2 :

false*/

public class RatInAMaze {

public static boolean solveMaze(int[][] maze, int i, int j, int[][] path) {

// Checking if the current cell which we are going to traverse is a valid cell or not?

if (i < 0 || i >= maze.length || j < 0 || j >= maze.length || maze[i][j] == 0 || path[i][j] == 1) {

return false;

}

// Including the current cell to be in path[i][j]

path[i][j] = 1;

// Checking if the current cell is destination cell or not

if (i == maze.length - 1 && j == maze.length - 1) {

// printing the path before returning

print2dArray(path);

return true;

}

// Explore further the maze in all direction

// Top Direction

if (solveMaze(maze, i - 1, j, path)) {

return true;

}

// Right Direction

if (solveMaze(maze, i, j + 1, path)) {

return true;

}

// Bottom Direction

if (solveMaze(maze, i + 1, j, path)) {

return true;

}

// Left Direction

if (solveMaze(maze, i, j - 1, path)) {

return true;

}

return false;

}

public static boolean ratInAMaze(int[][] maze) {

int[][] path = new int[maze.length][maze.length];

return solveMaze(maze, 0, 0, path);

}

public static void print2dArray(int[][] arr) {

System.out.println("-----------------");

System.out.println("Path of the Maze:");

System.out.println("-----------------");

for (int i = 0; i < arr.length; i++) {

for (int j = 0; j < arr.length; j++) {

if (arr[i][j] != 0)

System.out.print("🐀" + "\t");

else

System.out.print("🧱" + "\t");

}

System.out.println();

}

System.out.println("-----------------");

}

public static int[][] takeMazeInput() {

Scanner scan = new Scanner(System.in);

System.out.print("Size of the Maze = ");

int size = scan.nextInt();

int[][] maze = new int[size][size];

for (int i = 0; i < maze.length; i++) {

for (int j = 0; j < maze[i].length; j++) {

System.out.print("Maze [" + i + "][" + j + "] = ");

maze[i][j] = scan.nextInt();

}

}

return maze;

}

public static void main(String[] args) {

// int[][] maze = takeMazeInput();

int[][] maze = {

{1, 1, 0},

{1, 1, 0},

{0, 1, 1}

};

System.out.println(ratInAMaze(maze));

}

}