I was initially scheduled for an on-site interview due to a referral. Three days later, I received a call from one of the interviewers informing me of a Skype call with the company founder scheduled for the following week. Three days after that Skype call, the same interviewer contacted me again to offer me the position.

The on-site interviews were entirely coding-based. I encountered questions that initially appeared easy but proved challenging, alongside others that were difficult from the outset. I required assistance with at least a quarter of them, and the interviewers helped me debug two. I was unable to answer one question. Despite being grueling, it was, in some ways, an interesting and fun experience.

Overall, this company is quite intense. One of the first things I noticed during my on-site interview was the employees' passion for coding and for working alongside others who share their enthusiasm for technology. They are all extremely intelligent and thrive in such an intellectually stimulating environment, where they can support each other on projects and work on diverse tasks. This also means many of them are qualified to interview candidates. During my on-site visit, I was there for nine hours and was interviewed by five different people, for one hour each.

If you are interviewing here, remember to be yourself. Although you will be interviewed alongside master's student candidates, and possibly even individuals from other countries, authenticity is paramount. While it might seem that at such a high-stakes company you should present your absolute best, it is especially important to be genuine. Do not exaggerate your capabilities, and at the same time, do not be intimidated by extravagant perks, such as a limousine service to the company. They are seeking a good fit, which is a hard worker who is intelligent but does not disrupt the atmosphere of equality among all employees. Certainly, a certain degree of professionalism is required to secure this role, but this is equally important.

Implement the C function atoi.

Implement a hash set.

Implement an iterative deepening algorithm.

Given a list of "threads", which contain two variables – starting and ending times – implement a function that will return all running threads at some time t. Optimize it (faster than O(n)).

Suppose you have a single-column table of entries of variable size. Implement this table to also contain methods to lengthen one cell, cut a cell shorter, and to return which cell we're pointing at if given a certain distance from the beginning of the table. All methods need to be fast (assume a single-column table with many entries).