Docker Front End Engineer interview questions

Had an initial call with recruiter to go over background and process. Initial tech screen had to be rescheduled and then later was assigned a different interviewer. The tech screen was building a game (algorithm, not UI) and heard no feedback for a week. Later was told it went "well" but that I needed to interview with someone on the frontend team. The next tech screen was very bizarre. I was asked to develop an algorithm in a very specific way, which introduced difficulties as I wasn't aligned with his implementation strategy and didn't truly understand why it was needed. Apparently, he was looking for an abstract syntax tree and recursion. Apparently, the abstract syntax tree example was from an "introduction to programming" book which is laughable.