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Sort by start time, use min-heap to track room end times, reuse rooms when available.
Example:
Input:
intervals=[[0,30],[5,10],[15,20]]Output:
2 (need 2 rooms max)Common Mistakes:
- Not sorting by start time first
- Using max-heap instead of min-heap
- Not removing freed rooms before adding new ones
- Greedy removal of all freed rooms (should only remove one)
Notes:
Heap tracks end times of ongoing meetings. Time O(n log n), Space O(n). Alternative: separate start/end arrays sweep line. Premium problem.
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Sort by start time, use min-heap to track room end times, reuse rooms when available.
Example:
Input:
intervals=[[0,30],[5,10],[15,20]]Output:
2 (need 2 rooms max)Common Mistakes:
- Not sorting by start time first
- Using max-heap instead of min-heap
- Not removing freed rooms before adding new ones
- Greedy removal of all freed rooms (should only remove one)
Notes:
Heap tracks end times of ongoing meetings. Time O(n log n), Space O(n). Alternative: separate start/end arrays sweep line. Premium problem.
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Meeting Rooms II