Finding Duplicates in Records | Dataford Interview Questions

World Wide Technology data pipelines may receive repeated records during ingestion retries. Given a list of record dictionaries, return the record IDs that appear more than once.

A record is considered a duplicate when its record_id has already appeared earlier in the list. Return each duplicated ID only once, in the order it is first identified as a duplicate.

Formal Specification

Implement find_duplicate_records(records).

Input: records, a list of dictionaries. Every dictionary contains an integer record_id and may contain other fields.
Output: A list of integer record IDs that occur at least twice.
The input list must not be modified.

Constraints

0 <= len(records) <= 100,000
Each record contains a valid integer record_id
-10^9 <= record_id <= 10^9
The input list must not be modified

Function Signature

def find_duplicate_records(records):

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