Navigate unknown maze to find target

You are given an exploration interface for an unknown 2D maze that exposes only local actions (e.g., move(up/down/left/right) -> bool indicating success, position() -> (r,c), and atCheese() -> bool). Starting from an initial cell, design an algorithm to find the cheese with the fewest steps if it is reachable, minimizing redundant moves. You may adapt/override the interface to enable breadth-first exploration on the fly (e.g., by building a discovered map and backtracking). Specify visited-state representation, frontier management, termination conditions, and complexity in terms of reachable cells. Follow-up: Propose unit tests, including obstacles at start, multiple cheeses, unreachable cheese, loops, unknown bounds, and large open areas.