Event Scheduling App – Conflicts and Sorting | Dataford Interview Questions

Take-home: given a JSON file of events (title, start time, end time), build a simple app that lists the events sorted by start time and marks which events conflict in time with others; explain the algorithm choice and time/space complexity. Due in 3 days.

Asked in the take-home project stage. Offered as an alternative to the algorithm phone screen; followed by a call with a Facebook engineer to discuss the approach.

Input and Output

Implement def mark_conflicting_events(events):. Each event is a dictionary with string fields title, start_time, and end_time, using ISO 8601 timestamps. Return copied event dictionaries sorted by start_time, adding boolean conflicts. Two events conflict when one starts before the other ends. Events touching at an endpoint do not conflict.

Example: [A 09:00-10:00, B 09:30-11:00] returns both with conflicts: true. Non-overlapping events return false.

Constraints

1 <= len(events) <= 100000
Each event contains title, start_time, and end_time
Timestamps are valid ISO 8601 values in the same timezone
start_time is earlier than end_time
Events that share an endpoint do not conflict

Function Signature

def mark_conflicting_events(events):

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