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Team Teach Homework

Maze Solver Problem

Instructions

Your task is to write a method solveMaze(char[][] maze, int startX, int startY) that determines whether a path exists from a starting point (startX, startY) in a 2D maze to the exit marked as 'E'. Use recursion to explore the maze.

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Requirements

Input

• A 2D array of characters (char[][] maze) representing the maze.

• An integer startX indicating the row index of the starting point.

• An integer startY indicating the column index of the starting point.

Output

• Return true if there is a path from (startX, startY) to 'E'.

• Return false if no such path exists.

Maze Rules

• ' ' represents an open path (you can move here).

• '#' represents a wall (you cannot move here).

• 'E' represents the exit (this is the destination).

Movement

• You can move up, down, left, or right to adjacent cells.

• You cannot move diagonally or leave the bounds of the maze.

Marking Visited Cells

• To avoid revisiting the same cells, mark visited cells as '#' temporarily during recursion. Restore them to ' ' after backtracking.

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Steps to Solve

1. Check if the current position is valid:

   • Is it within the bounds of the maze?

   • Is it an open path or the exit?

2. Check if the current position is 'E'. If yes, return true.

3. Mark the current cell as visited (change it to '#').

4. Recursively explore all possible directions (up, down, left, right).

5. If any direction leads to the exit, return true.

6. Restore the cell to ' ' after exploring (backtracking).

7. If no paths lead to the exit, return false.

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public class SkibbidiSolutions {

    public static boolean solveMaze(char[][] maze, int startRow, int startCol) {
        if (maze[startRow][startCol] == '#' || maze[startRow][startCol] == 'E') {
            return maze[startRow][startCol] == 'E';
        }

        return floodFill(maze, startRow, startCol);
    }

    private static boolean floodFill(char[][] maze, int row, int col) {
        if (row < 0 || row >= maze.length || col < 0 || col >= maze[0].length) {
            return false;
        }

        if (maze[row][col] == '#' || maze[row][col] == 'V') {
            return false;
        }

        if (maze[row][col] == 'E') {
            return true;
        }

        maze[row][col] = '#';

        boolean foundPath = floodFill(maze, row - 1, col) ||
                            floodFill(maze, row + 1, col) ||
                            floodFill(maze, row, col - 1) ||
                            floodFill(maze, row, col + 1);

        return foundPath;
    }
}

//Test Case 2: Starting at the Exit


char[][] maze = {
    {'#', '#', '#', '#', '#'},
    {'#', ' ', ' ', '#', 'E'},
    {'#', ' ', '#', ' ', '#'},
    {'#', ' ', ' ', ' ', '#'},
    {'#', '#', '#', '#', '#'}
};
SkibbidiSolutions skibbidi=new SkibbidiSolutions();
System.out.println(skibbidi.solveMaze(maze, 1, 4)); // Output: true
char[][] maze2 = {
    {'#', '#', '#', '#', '#'},
    {'#', ' ', '#', '#', 'E'},
    {'#', ' ', '#', '#', '#'},
    {'#', ' ', ' ', ' ', '#'},
    {'#', '#', '#', '#', '#'}
    };
    
    System.out.println(skibbidi.solveMaze(maze2, 3, 1)); // Output: false

char[][] maze3 = {
    {'#', '#', '#', '#', '#'},
    {'#', ' ', ' ', ' ', 'E'},
    {'#', ' ', '#', ' ', '#'},
    {'#', ' ', ' ', ' ', '#'},
    {'#', '#', '#', '#', '#'}
    };
    
    System.out.println(skibbidi.solveMaze(maze3, 1, 1)); // Output: true

true
false
true