The Event Broadcaster
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
Implement an EventEmitter that supports on(event, listener), emit(event, payload), and off(event, listener). Listeners are opaque identifiers (strings in the tests). emit notifies every listener currently subscribed to the event by appending the payload to the result list once per listener (so a 3-listener emit returns [payload, payload, payload]); an emit with no listeners returns []. off removes one matching listener identifier (the first one found if duplicates exist). Then implement a driver event_broadcaster(op_names, op_args) that constructs an EventEmitter when op_names[0] is 'EventEmitter' and dispatches the remaining 'on'/'emit'/'off' ops with their parallel arg lists. Return the list of results in op order: None for the constructor, on, and off; the per-listener payload list for emit.
Summary
Subscribers show up, listen, and sometimes leave.
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