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Yes, Zigzag Iterator or similar iterator design problems appear in interviews at companies like Google, Meta, and Amazon. They test understanding of iterators, queues, and clean object-oriented design.
The optimal approach uses a queue to store iterators or index pointers for each list. Each time next() is called, the front iterator is used to fetch an element and reinserted if more elements remain. This maintains alternating order efficiently.
Yes. The queue-based approach easily generalizes to k lists. Simply enqueue iterators for all non-empty lists and keep cycling them until all elements are consumed.
A queue is the most suitable data structure because it naturally supports round‑robin traversal. By pushing iterators back into the queue after consuming an element, we maintain the zigzag sequence cleanly.