Your question is Data Structure Trade-offs. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Can you describe the trade-offs between different data structures in a specific project?
Discuss the structures you selected, the access patterns and constraints that influenced the decision, and how alternatives would have affected performance, memory usage, ordering, mutability, and concurrency. Use specific type names and one concrete code-level example.
Keep the discussion focused on standard data structures and their practical behavior in a production codebase.