Hello xuan.nguyen.swe,

We have provided two approaches towards the estimation problem. The first one is technically sound but less plausible, while the second one seems practical. We preferred using the second approach because it is plausible as it is based on back-of-the-envelope calculations, which are considered rough. As far as Interviews are considered, it is a highly subjective debate. Interviewers can ask a variety of questions, and candidates can only debate on them. Regarding this very point, just like we said before, it will take more parameters and a lot more calculations, simulations, and the practical infrastructure to find accurate answers. There may be no rule of thumb here because different tech giants may use different approaches to meet their needs. At the end of the day, we have to make assumptions that can lead to plausible and reasonable answers, which is just the case here. Also, in interviews, evaluators assess candidates for all the sections of the interview and not just one portion.

I hope now your point is cleared. Let me know for further clarification.

Thank you