The Repeat Visitor
A medium Python mock interview question on DataDriven. Practice with AI-powered feedback, real code execution, and a hire/no-hire decision.
- Domain
- Python
- Difficulty
- medium
- Seniority
- L4
Interview Prompt
You're combing purchase logs for a retail loyalty team, where each record carries a `user` and a `date` string in 'YYYY-MM-DD' format and the records arrive in no particular order. A user counts as a repeat visitor if two of their purchases fall no more than `days` apart on the calendar. Return the IDs of those users sorted alphabetically, and an empty list when nobody qualifies.
Summary
Loyal customers come back sooner than expected.
How This Interview Works
- Read the vague prompt (just like a real interview)
- Ask clarifying questions to the AI interviewer
- Write your python solution with real code execution
- Get instant feedback and a hire/no-hire decision