I got the basic idea pretty fast, treat each door as a directed edge rather than a bidirectional one.
Model the maze as a graph where each cell is a node and edges represent possible moves, but directional doors require edge attributes. For each door, store the allowed direction(s) of passage and during traversal (BFS/DFS) only consider an edge if the current movement direction matches the door's allowed direction. Clearly separate the maze representation from the traversal algorithm to handle the added constraints.
Pro tip: Emphasize that directional doors are essentially directed edges in the graph; this abstraction simplifies both modeling and traversal. Also, mention that you would validate the solution with edge cases like doors on the maze boundary or cycles of one-way doors.
Ask whether doors can be bidirectional, if multiple doors can exist between same cells, and if the maze is grid-based. Confirm that movement is only allowed in four cardinal directions unless specified otherwise.
Represent each cell as a node. For each door, add a directed edge from the source cell to the destination cell only if passage is allowed in that direction. For open passages, add edges in both directions.
Use BFS or DFS, but when exploring neighbors, only follow edges that exist in the graph. This naturally enforces the directional constraints of doors.
Consider doors that allow multiple directions (e.g., from north and east) by adding multiple directed edges. If performance is critical, discuss using adjacency lists with direction flags or bitmasks to encode allowed directions.
Walk through examples: a door that only allows entry from the north should not be traversable from the south. Test with cycles of one-way doors to ensure traversal terminates correctly.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.
First, clarify the problem context: this is likely about pathfinding or motion planning where a door's allowed direction is a constraint. Explain that if the direction points into a wall, the path is invalid and must be blocked. Then describe how to detect this geometrically and ensure the solver treats it as an obstacle, possibly by adding a virtual barrier or adjusting the graph.
Pro tip: Mention that you would add a unit test for this edge case and consider using a conservative collision check to avoid tunneling. Also, discuss trade-offs between precomputing blocked directions and runtime checks.
Restate the problem: a door has an allowed direction (e.g., one-way passage) that points into an adjacent wall, making it impassable. Confirm assumptions about the environment representation (grid, graph, geometry).
Explain how to check if the door's direction vector intersects a wall. This could be done via raycasting, checking grid cells, or using geometric intersection tests.
Describe how to modify the solver's representation: mark the door as blocked, remove the edge, or add a virtual obstacle. Ensure the solver does not attempt to traverse it.
Discuss handling partial overlaps, thin walls, or dynamic environments. Suggest adding assertions or unit tests to catch such cases.
Compare precomputing blocked doors vs. runtime checks, and consider performance implications for large maps.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.