Topics: Algorithms, System Design, Breadth-First Search, Graph Traversal
Location: Menlo Park, CA
Interview date: 2025-12-28
Summary
Round 1: Coding (AI Assisted)
Question: Maze Solver with four parts. The first part involves debugging print statements to check for null values. The second part requires checking if a node has been visited in BFS. The third part adds a one-way chute to the BFS. The fourth part requires picking up keys to open doors, which changes the visited logic.
Round 2: System Design
Question: Design a variation of Facebook Live Comments.
Details
Coding Round Details
The coding question involved a maze solver with increasing complexity:
Part 1: Debugging print statements to handle null values by printing '*'.
Part 2: Implementing Breadth-First Search (BFS) and checking if nodes have been visited. I needed to be careful because the code base was confusing on a small screen.
Part 3: Adding a one-way chute to the BFS, which made the direction logic more complex. I found that AI assistance was limited in this part.
Part 4: Implementing a key-door system where keys ('a') open corresponding doors ('A'). This required modifying the visited logic because picking up a key on one path could allow me to revisit another path.
System Design Round Details
The system design round focused on designing a variation of Facebook Live Comments.
Preparation Tips & Key Takeaways
What I Learned
Using a larger screen is crucial to avoid wasting time due to code being too compact.
AI assistance can be limited when dealing with complex logic and direction-related issues.
Recommended Preparation
Coding Practice
Practice debugging maze-solving algorithms.
Focus on BFS and graph traversal algorithms.
System Design
Study system design principles for high-volume live comment systems.
Common Pitfalls to Avoid
Small screens can lead to wasted time due to code compactness.
Relying too much on AI without thoroughly understanding the underlying logic can be problematic.