What is the minimum number of meeting rooms required for overlapping meetings?
An interval scheduling problem that tests your ability to manage overlapping ranges and optimize resource allocation.
Why Interviewers Ask This
This problem evaluates your skill in sorting intervals and using efficient data structures like heaps to track active resources. It simulates real-world scenarios where managing limited resources (rooms, servers) is critical. The interviewer looks for an optimal solution better than brute force.
How to Answer This Question
Sort the meetings by their start times. Use a min-heap to keep track of the end times of ongoing meetings. Iterate through the sorted meetings; if the current meeting starts after the earliest ending meeting, remove that meeting from the heap. Add the current meeting's end time to the heap. The heap size at the end represents the minimum rooms needed.
Key Points to Cover
- Sorting by start time
- Min-heap for end times
- Greedy approach
- Heap size tracking
Sample Answer
I would first sort all meetings by their start times. Then, I'd use a priority queue (min-heap) to store the end times of the meetings currently occupying rooms. For each new meeting, I check if its start time is greater…
Common Mistakes to Avoid
- Using nested loops leading to O(n^2)
- Incorrect heap update logic
- Failing to sort inputs
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