I was contacted due to an open-source software I created in a very specific area. After two phone interviews that were closely related to topics close to my software, I was invited to an on-site interview.

The questions I received there were mostly general algorithmic questions, such as writing functions for a given task. For example, "What is a deadlock? Give a code example that might cause one." There were also questions about modifications and filtering of raw buffer data using bit operators.

Most of it was out of my comfort zone, as my expertise and the prospective job are in very different areas. I had to improvise a lot, especially for the deadlocks and buffer data questions. There were surprisingly few questions concerning the area for which I thought I was invited.

One of the questions completely lost me, and I was not able to grasp that the interviewer was trying to suggest a different approach. I also did not take the opportunity after the interview to ask for the actual solution, which might have led to a fruitful reflection on my admittedly silly attempts.

I haven't yet received an answer. For now, I'll set it to "No offer," as that reflects what my gut feeling tells me.

1. Find the longest sequence of consecutive neighbors in a square matrix of size n^2, with random entries from 0 to n^2. Neighbors are defined as top, left, bottom, and right entries.

2. Find the n-th digit of a number constructed by the concatenation of all natural numbers.