Basic data structure runtime questions and DSA quirks, followed by code for two problems. It was a one-hour interview, where I had to fully explain my thought process at each stage. They wanted to understand what I was thinking before letting me code. The majority of the time was spent on coding and a little bit on runtime analysis. They care about correctness over anything else, mostly. So, for the first stage, don't worry about optimality. Just focus on being correct and ask clarifying questions.

To be concise and fully explain my thought process.