Started with a deque and felt pretty good about it until the thread-safety part came up.
Start by clarifying requirements and constraints, then propose a circular linked list with a hash map for O(1) add/remove and O(1) next-task retrieval. Discuss thread-safety using fine-grained locks or lock-free techniques, and analyze time/space complexity for each operation.
Pro tip: Mention that a simple circular linked list can starve tasks if tasks are added/removed frequently; propose a solution like maintaining a separate queue for new tasks or using a timestamp-based fairness mechanism to ensure no starvation.
Ask about expected load, task priorities, fairness guarantees, and concurrency requirements to tailor the design.
Propose a circular linked list for round-robin order and a hash map for O(1) task lookup and removal.
Discuss locking strategies (e.g., fine-grained locks per task or a global lock) or lock-free approaches using atomic operations.
State time complexity for add, remove, and next operations (all O(1) with proposed structures) and space complexity O(n).
Explain how the design prevents starvation, handle empty scheduler, and consider dynamic task addition/removal.
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