Merge K Sorted Arrays and Event Streams

Problem Overview

The round: merging sorted inputs, in three onsite reports from June to September 2026, each asking a different shape. In one five-round onsite (August 2026) the last coding question was a simplified merge-k: merge three sorted arrays into one sorted, de-duplicated array; the follow-up asked for k arrays. Another onsite…

• 3 candidate-reported follow-ups — the exact probes interviewers asked, with the trigger for each
• The rest of the problem statement — full requirements, constraints, and edge cases
• Approach and trade-offs — what passing candidates did, and the mistakes that sink people