Seen this one before on prep forums so I wasn't totally blindsided.
Clarify the grid dimensions, movement rules, and whether the robot must navigate to a target or just simulate instructions. Then choose an appropriate representation (e.g., 2D array, coordinate system) and algorithm (e.g., simulation, BFS/DFS for pathfinding), and discuss time/space complexity.
Pro tip: At Uber, emphasize robustness: discuss handling invalid moves, obstacles, and edge cases like grid boundaries, and mention how you'd test your solution with unit tests.
Ask about grid size, movement rules (e.g., directions, step size), obstacles, and whether the goal is to simulate or find a path. Confirm input/output format.
Decide how to represent the grid (2D array, coordinate system) and robot state (position, direction). Consider using a set for obstacles if needed.
For simulation, iterate through instructions updating position. For pathfinding, use BFS/DFS/A* depending on grid size and obstacles. Handle boundary checks and invalid moves.
State time and space complexity. For simulation, O(n) where n is number of instructions. For BFS, O(rows*cols).
Walk through examples, including edge cases like starting at boundary, obstacles blocking path, or instructions causing out-of-bounds moves.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.