Sum of Their Parts

A medium Python interview practice problem on DataDriven. Write and execute real python code with instant grading.

Domain

Python

Difficulty

medium

Seniority

L4

Problem

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.

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