In-Memory DB: Track per-key operation counts and return Top N keys

Problem: In-Memory DB Variant — Track per-key operation counts and return Top N keys You are implementing a simplified in-memory database that stores data as key -> record. In this variant, every time an operation is performed on a given key, you must increment that key's operation count by 1. You also need to support querying the Top N keys with the highest operation counts. Required functionality Maintain an in-memory structure to support the database operations on a key (the exact operation set is defined by the OA statement). Maintain a counter opCount[key]: increment it by 1 for every operation that targets key. Implement a query API that returns the Top N keys sorted by operation count in descending order. Output For TopN query, output the list of keys ordered by decreasing operation count. Constraints N is a positive integer. The count is associated with the key (not with individual fields inside the record). Note: The original post does not include the full I/O format, the complete operation list, or tie-breaking rules. Follow the OA prompt for those details. Example Input N/A (depends on OA command format) Output N/A