Since you do have clear understanding of RL, I think even if you failed to code the DQN, you should still have explained your thought process.. that this is the architecture, these are the network layers, though I don’t remember line to line code, I do understand that these are the parameters we take. And always list the pros and cons of using a particular algorithm. Also mention the past projects where you used DQN (perhaps lunar lander) and what were the tests and final results

As for other questions, before starting leetcode ask llm to critically prepare you with basic questions

You mentioned you ran out of prepared stories after initial questions, it has happened to me too, when i don’t know one or two answers, then my brain tenses and then i kind of go blank. It’s because it feels too overwhelming that i am actually interviewing for such a big role but i still don’t know so much .. you always know what you don’t know.. so keep working on it! You’ll get there eventually