Sum of Their Parts
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 collapsing a raw event stream into one record per user, where each event carries a `user_id`, an `event_type`, and an `amount`. For every user, total their amounts within each `event_type` so each distinct type becomes one key on that user's record, keeping only the types that user actually triggered (absent types stay absent, not zero). Order each record's `event_type` keys from highest total to lowest with `user_id` last, and return the records sorted by `user_id` ascending.
Summary
A stream of raw actions, folded into one portrait per person.
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