Rat in a Maze Problem in DSA Typescript - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if the rat can move to the next cell safely.

DSA Typescript

function isSafe(maze: number[][], x: number, y: number): boolean {
  return x >= 0 && y >= 0 && x < maze.length && y < maze[0].length && maze[x][y] [1] 1;
}

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A>

B!=

C==

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '!=' instead of '==' causes wrong path checks.

Not checking boundaries leads to errors.

The rat can move to the cell only if the cell value is 1 (open path). So we check if maze[x][y] == 1.

2fill in blank

medium

Complete the code to mark the current cell as part of the solution path.

DSA Typescript

function solveMazeUtil(maze: number[][], x: number, y: number, sol: number[][]): boolean {
  if (x === maze.length - 1 && y === maze[0].length - 1) {
    sol[x][y] = [1];
    return true;
  }
  if (isSafe(maze, x, y)) {
    sol[x][y] = 1;
    // rest of code omitted
  }
  return false;
}

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A1

B0

C-1

D2

Attempts:

3 left

💡 Hint

Common Mistakes

Marking with 0 instead of 1 causes no path to be recorded.

Using negative values is incorrect.

Marking sol[x][y] as 1 means this cell is part of the solution path.

3fill in blank

hard

Fix the error in the recursive call to move down in the maze.

DSA Typescript

if (solveMazeUtil(maze, x [1], y, sol)) {
  return true;
}

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A- 1

B+ 1

C* 1

D/ 1

Attempts:

3 left

💡 Hint

Common Mistakes

Using '- 1' moves up, not down.

Using '* 1' or '/ 1' does not change position.

To move down, increase the x coordinate by 1 (x + 1).

4fill in blank

hard

Fill both blanks to move right and backtrack correctly.

DSA Typescript

if (solveMazeUtil(maze, x, y [1], sol)) {
  return true;
}
sol[x][y] = [2]; // backtracking

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A+ 1

B- 1

C0

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Using '- 1' moves left, not right.

Setting backtracking to 1 keeps the cell marked.

To move right, increase y by 1. For backtracking, reset sol[x][y] to 0.

5fill in blank

hard

Fill all three blanks to complete the main function that initializes and starts the maze solving.

DSA Typescript

function solveMaze(maze: number[][]): number[][] | null {
  const sol = Array(maze.length).fill(null).map(() => Array(maze[0].length).fill([1]));
  if (solveMazeUtil(maze, [2], [3], sol)) {
    return sol;
  }
  return null;
}

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A0

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Initializing solution matrix with 1 causes wrong path.

Starting from other than (0, 0) misses the maze start.

Initialize solution matrix with 0s. Start solving from position (0, 0).