Coding questions · Pinterest

Implement Binary Search for Policy Violation Logs

This question evaluates understanding of algorithmic search and data manipulation skills, specifically applying binary search over date-ordered logs and composing efficient queries using SQL and Python.

violations

+--------+---------+---------------+
| pin_id | type    | violation_date|
+--------+---------+---------------+
|   0    | spam    | 2022-01-03    |
|   1    | spam    | 2022-01-03    |
|   0    | privacy | 2022-01-03    |
|   2    | child   | 2022-02-06    |
|   3    | spam    | 2022-02-10    |
+--------+---------+---------------+

Scenario

Pinterest wants to query pins that violated specific policies quickly from daily logs.

Question

Write SQL/Python to return all pin_ids that violated a given policy type. Logs are date-sorted; add a function that, for a (policy, start_date, end_date), returns the matching pins using binary search rather than full scan.

Hints

Create index on (type, violation_date); in Python, bisect left/right on pre-sorted list of dates.