I was contacted by a recruiter on LinkedIn and started the interview process. He was transparent, prompt, and supportive throughout the process. He updated me on every step and detail. His promptness, such as getting feedback within three hours of a phone interview, speaks for itself.

Then, I had an on-site interview. Three interviewers liked my answers. They particularly liked my system design and thinking. However, one interviewer apparently didn't like my coding style. I was asked to come for one more interview just to check the coding part again.

So, a tip: use a whiteboard better. Apparently, working and clean code isn't enough; it needs to look clean on the board as well.

Overall, the process was positive. But, I had the feeling that some interviewers were inexperienced and focused on the wrong things. Also, a big difference from other companies: they expect you to be really fast (meaning you need to know the answer upfront). If you don't know the answer upfront but come up with a solution after thinking, trying, making mistakes, and optimizing, it doesn't count—at least, it didn't in my case. They expect you to solve a problem, implement it, and test it on the board in 15-20 minutes.

Advice for FB: train your interviewers to focus on skills, NOT memorized answers.

I have offers from big companies/competitors, so I will just go with them.

The question is verbose and uses concepts like search engines and string matching, but at its core, it boils down to this: Given a two-dimensional array where each sub-array (row) is sorted, for example:

[[1, 1000, 2000] [20, 10001, 5000] [55, 10002, 222222]]

Find a minimum range that contains at least one number from each row. For the array above, the range should be (1000-1002).