Nice list, but a side-note: all this focus on interview-preparation may give the false impression that algorithms and data structures is a closed body of work,

Nice list, but a side-note: all this focus on interview-preparation may give the false impression that algorithms and data structures is a closed body of work, when in fact it is an active and lively field of research with many basic questions not yet understood. Someone could go through these 500 questions and for (almost) all of them formulate variants/extensions that would be open research questions. Or alternatively, ask for each of them: is this the best possible solution? Can I prove it? What if I restrict what the algorithm can do? What if the data comes online? What if the input is noisy? etc. etc. etc.