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Navigate unknown maze to find target

Last updated: Mar 29, 2026

Quick Overview

This question evaluates understanding of graph traversal and exploration algorithms, representation of visited state and frontiers, path optimality, and complexity analysis in an environment constrained to local actions.

  • Medium
  • Meta
  • Coding & Algorithms
  • Software Engineer

Navigate unknown maze to find target

Company: Meta

Role: Software Engineer

Category: Coding & Algorithms

Difficulty: Medium

Interview Round: Technical Screen

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.

Quick Answer: This question evaluates understanding of graph traversal and exploration algorithms, representation of visited state and frontiers, path optimality, and complexity analysis in an environment constrained to local actions.

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Meta
Sep 6, 2025, 12:00 AM
Software Engineer
Technical Screen
Coding & Algorithms
1
0

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.

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