The standard meeting rooms problem I'd done before, but the cyclic part broke my initial solution completely.
First, clarify that meetings can wrap around midnight, so the schedule is cyclic. Then, transform the problem into a circular interval graph coloring problem, and use a sweep-line algorithm with a circular array or a priority queue to find the maximum overlap, which equals the minimum rooms needed.
Pro tip: Mention that you can break the cycle by duplicating the day (e.g., consider times modulo 1440 and extend meetings that wrap) to reduce it to a linear sweep, showing you understand how to handle cyclic data without overcomplicating.
Confirm that meetings can wrap around midnight, meaning the schedule repeats daily, and ask if meetings can be longer than 24 hours or if there are any constraints on the number of meetings.
Decide to represent time in minutes from 0 to 1439, and handle wrap-around by splitting a meeting into two intervals if it crosses midnight, or by duplicating the day and extending meetings that wrap.
Create events for meeting starts and ends, sort them by time, and sweep through the timeline while maintaining a count of active meetings. For cyclic, either sweep twice or use a circular array to find the maximum overlap.
The maximum number of concurrent meetings during the sweep is the minimum number of rooms required. Return that number.
Discuss time complexity O(n log n) due to sorting, and space O(n). Mention edge cases like meetings that exactly touch midnight, zero-length meetings, and all meetings overlapping.
AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.