USA | Benchling | Phone Screen
Summary
I had a collaborative phone screen at Benchling where I designed a traffic light system for a 4-way intersection, focusing on readable and maintainable code rather than LeetCode-style optimization.
Full Experience
This phone screen was a really fun and collaborative round for me. I was happy to work with the interviewer like colleagues on an interesting problem. We weren't allowed to use AI in this round, which was clearly stated.
The main task was to design a traffic light system for a standard 4-way intersection. I focused on communicating my assumptions based on real-world understanding to the interviewer, and he was very patient and attentive. The only follow-up question I got was about how I would improve the code prior to submitting it for review, which led to a good discussion.
Overall, I really liked this round and felt very relaxed. The interviewer was super nice and listened attentively.
Interview Questions (1)
You have a standard 4-way intersection (think the shape of a "plus"). You need to design a traffic light system. No starter code provided, just the requirements:
- Assume a standard traffic light system (red, yellow, green)
- A technician that maintains the traffic lights should be able to control the duration of yellow and green
- You need to implement a function that takes in
num_tickswhich is a positive integer and for each "tick", output the light color for the traffic lights in the intersection. - Anything you'd expect in a real traffic light system is fair game and should be accounted for. Do communicate your assumptions though
The expectation:
- Don't focus on time and space complexity here like you'd do in a LeetCode problem.
- You should optimize for writing readable, maintainable, and extensible code like you would in a real engineering setting.
Preparation Tips
My preparation for this round centered on thinking about good design principles rather than typical LeetCode algorithm optimization. I focused on communicating assumptions clearly, designing maintainable and extensible code, and using appropriate OOP concepts for interfaces and data representation. The key was to write readable code as if for a real engineering setting, rather than just demonstrating algorithm knowledge.