AppsFlyer Software Engineer interview questions

Was interviewed by an engineer who asked me various overall questions about myself and they talked a bit about their specific job. It was not a very good impression as they seemed a bit negative in general, and had this attitude that the other departments and company leadership were mostly making trouble for them. I was told I could do the question in any programming language I wished, so I chose one I liked. About half-way through I was told "oops, actually do it in this other language instead and start over", which was a bit stressful. I was also asked to stop talking to myself while I was trying to solve the task. While solving it, I was also interrupted and told I could not use a built-in library but re-implement one myself, which I found was odd, as in my experience it is positive that the candidate knows of what kind of powers the language offers a developer.

Face-to-face technical interview with team leader who asked me technical questions and asked me to answer them on a whiteboard and explain my thought and the way to the solution