Intervals Pattern
Interval problems almost always start by sorting on the start (or end) time, then sweeping once while tracking the current interval. That single sort unlocks merging, insertion, and overlap counting.
Typical complexity: O(n log n) time (dominated by the sort), O(n) space
When to use it
- The input is a set of ranges, meetings, or time windows.
- You need to merge, insert, or count overlaps.
- You're scheduling with the fewest resources.
Practice problems
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