Roblox IC3 interview (passed) | Recruiter says this is max TC for the level, but needs relocation
Summary
I successfully passed the IC3 interview at Roblox and received an offer. I found the process unique, featuring a CodeSignal OA, a deep-dive system design round, a coding round focusing on callstack analysis, a distinctive creativity round, and a behavioral round emphasizing high-scale systems.
Full Experience
I'm happy with the offer I got, but wanted to share my experience going through the interview process since I felt that it's pretty unique compared to other companies. The creativity round kind of reminds me of when Google used to ask for brainteasers as part of the interview loop in the pre leetcode based days. While the offer is great, I'm not really sure if I really want to move to San Mateo for this, it seems pretty different from what I'm used to and I'm not really sure if I'm ready for that change.
OA Round
The process started off with a CodeSignal OA, the time was tight but I was able to snag a pic of some of it. I'd say it's not a hard problem but make sure to keep an eye on the time.
System Design Round
Got asked about designing a system to similar to a like/unlike system but for Roblox. This felt like one of the hardest system design interviews I've gone through. Just like the behavioral round I'll talk about later this one was very focused on handling high levels of scale. The system itself that I designed was not too complicated at a high level but the interviewer really dug deep into every detail. Much like the creativity round I'll talk about below, the System Design rounds from what I've seen, also tend to be focused around Roblox specific twists, or gaming specific twists. There's an example of one of these on this leetcode post: https://leetcode.com/discuss/post/7291528/roblox-system-design-by-anonymous_user-guid/
Coding Round
I was given a callstack as input and asked to find the function that was called the most frequently. This one didn't feel too difficult but there are a lot of edge cases to consider. I heard roblox interviews don't really like it if you aren't able to oneshot the solution and spend a lot of time debugging. I don't really agree with this requirement, but I guess have to try to adjust to their standard.
Luckily this question is leaked on question bank sites like this, so I had a good idea already of which edge cases I needed to handle and just made sure to go slow enough not to make any stupid mistakes. General rule of thumb I found helpful for any coding round.
Creativity Round
This is without a doubt the most unique round at Roblox. I was asked the classic elevator question. For this round my recommendation is to practice trying to think creatively about systems that you interact with throughout the day. If going into a coffee shop and having a bad experience, think about how you could make it better. I was able to find some of these on offerretriever, from what I saw a lot of these questions seem to be about things related to Roblox or gaming, so if you're not familiar with Roblox, I'd recommend to try and get familiar with it. This round is not only looking for creative solutions, but also feels like a bit of a culture fit check.
Behavioral Round
The only thing Roblox seemed to different in this round was a high emphasis on discussing high traffic and scale systems that I've worked on in the past. Seemed like there was more focus on that than in other senior level interviews. Other than that, it was your standard behavioral questions, nothing super special to do to prepare for this round.
Interview Questions (3)
Design a Like/Unlike System for Roblox at Scale
Design a system similar to a like/unlike system, adapted for Roblox, with a strong focus on handling high levels of scale. The interviewer dug deep into every detail.
Find Most Frequent Function in a Callstack
Given a callstack as input, find the function that was called the most frequently. Consider a lot of edge cases.
The Classic Elevator Design Question
Design or propose solutions for the classic elevator problem, emphasizing creative thinking about systems.
Preparation Tips
For the OA Round, make sure to keep an eye on the time.
For the Coding Round, I had a good idea of which edge cases to handle from leaked questions and made sure to go slow to avoid mistakes. A general rule of thumb I found helpful for any coding round is to be thorough.
The Creativity Round is unique. I recommend practicing creative thinking about everyday systems. For instance, if you have a bad experience at a coffee shop, think about how to improve it. Many questions seem to be Roblox or gaming-related, so familiarize yourself with Roblox if you aren't already. This round also functions as a culture fit check.
For the Behavioral Round, prepare for standard behavioral questions, but be ready to discuss past experiences with high traffic and scalable systems, as Roblox places a high emphasis on this for senior-level interviews.