I knew BFS immediately, got that part out fast.
Use BFS with 8-directional movement to find the shortest path, since BFS guarantees the shortest path in an unweighted grid. Track parent pointers for each visited cell to reconstruct the path from start to end, and handle edge cases like blocked start/end or no path.
Pro tip: Clarify whether diagonal moves are allowed to pass through blocked cells (e.g., if both adjacent orthogonal cells are blocked). Also, mention that BFS explores level by level, so the first time you reach the target, you have the shortest path.
Confirm movement rules (8 directions, diagonal allowed even if adjacent cells blocked?), grid boundaries, and what to return if no path exists. Check if start or end is blocked.
Use a queue for BFS, a visited set or 2D array to avoid revisiting, and a parent map or 2D array to store the predecessor of each cell for path reconstruction.
Start from (0,0), explore all 8 neighbors, skip blocked or out-of-bounds cells, and mark visited. Stop when reaching (n-1, n-1).
If target reached, backtrack from target to start using parent pointers, reverse the list, and return it. If queue empties without reaching target, return empty list or indicate no path.
State time and space complexity: O(n^2) since each cell visited once. Walk through a small example to verify correctness, including edge cases.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.