Clarify the problem constraints and edge cases, then propose a graph traversal algorithm like BFS or DFS. Explain the algorithm step-by-step, analyze time and space complexity, and discuss potential optimizations or trade-offs.
Pro tip: Mention that BFS is generally preferred for finding the shortest path, but DFS is simpler and sufficient if only connectivity is required. Also, discuss how to handle large grids by using iterative approaches to avoid stack overflow.
Ask about grid dimensions, movement constraints, and whether diagonal moves are allowed. Confirm if the start and target are guaranteed to be open.
Select BFS for shortest path or DFS for connectivity. Consider iterative implementations to avoid recursion depth issues.
Explain how to explore neighbors, mark visited cells, and terminate when the target is found or all reachable cells are exhausted.
State that time complexity is O(m*n) and space complexity is O(m*n) for the visited set and queue/stack.
Cover cases like start equals target, no path, or large grids. Mention in-place marking or bidirectional BFS for optimization.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.