Group Events by an Ordered Attribute List
Company: Mixpanel
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: medium
Interview Round: Technical Screen
Overview: Group encoded event rows by a caller-specified ordered list of attributes and return the nested counts as canonical compact JSON. This challenge tests dynamic map depth, field-position resolution, deterministic key sorting, repeated combinations, portable serialization, empty input, and output-aware complexity.