Very smooth with quick feedback. I learned a lot, and they were very helpful and friendly.

The phone coding interviews are slightly easier than the actual in-person interviews.

At the in-person interviews, focus on applying whatever you've learned. Don't try to do every single HackerRank or LeetCode problem and expect to do well. Apply all that knowledge!

Know exactly why you chose a certain data structure: Is it more efficient for reading or writing? How much space will that data structure you chose take on disk? If I chose a key-value store, then what will my keys be? Can I add more information to the key to make lookups faster?

Also, another tip: Don't overthink and complicate the answer. Simple answers are sometimes the best way to begin solving the problem.

I would suggest a 60/40 split between data structures and algorithms, respectively. Even if they provide hints to the right algorithm, you still need to determine your data structure and how you would store and retrieve that data.

For example, if you propose using a trie, you should be able to explain why, code it, modify it according to new constraints introduced on the spot, and discuss related concepts like suffix tries.