Clustered vs Non-Clustered Indexes | Dataford Interview Questions

What are the differences between clustered and non-clustered indexes?

Asked in the technical interview stage. Azure Data Engineer, 4-5 yrs exp.

Implement compare_indexes(records, key, query) using only Python data structures. A clustered index stores records ordered by key and locates matches with binary search. A non-clustered index preserves input order and maps each key to matching record IDs.

Input and Output

records is a list of dictionaries containing id and the selected key. Return clustered_ids, the matching IDs in sorted order, and non_clustered_ids, the matching IDs in original order.

Example: records with keys [30, 10, 20] and query 20 return matching ID lists containing the record with key 20. Duplicate keys must preserve their relative order.

Constraints

1 <= len(records) <= 10^5
Each record contains a unique id and the selected key
Key values are comparable and support ordering
Duplicate key values are allowed
The query value may have no matching record

Function Signature

def compare_indexes(records, key, query):

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