The interview process consisted of a phone interview with Karat, a contractor for Roblox. On their website, Karat prides itself on clearly stating the criteria they use for evaluation. The issue is that the actual decision of whether you move on or not in the interview process is made by Roblox, not Karat. As a result, you have two companies with different criteria deciding whether you are a good programmer, and this is confusing.

I managed to finish my programming challenge correctly (verified by my interviewer), which is Karat's most important criterion, and still failed. Was the code clean? No, I ran out of time for that. I focused on what Karat wanted to see from me, but not necessarily what Roblox prioritized.

So, my advice is to try your best to find out Roblox's criteria, as well as Karat's, and do your best to impress them both. It's hard enough to impress one company, but in this case, you have two.

For C++ programmers, the challenging part is not so much coming up with an algorithm, but rather remembering STL syntax. This is the sad part of this process: you can be rejected over something trivial to do in a normal job, but during the interview, you can't spend much time looking at Google because you'll run out of time.

This is where I struggled the most. STL is a big library, and if you don't use it every day, you won't remember it. Go over the more popular containers, know how to iterate through the elements, and hope you don't get template errors, as the diagnostic window will just dump lots of useless information at you. Focus on what's on the top.

Lastly, check if the editor has autocomplete; it usually does and it will help you remember.

If you don't have to use C++, don't. Python would be excellent for these tasks because the language is much easier.

Good luck.

Very easy algorithm question, but it required me to remember STL syntax, which I didn't.