Preview — Pro guide
You are seeing a portion of this guide. Sign in and upgrade to unlock the full article, quizzes, and interview answers.
Interval Patterns: Merge Intervals, Meeting Rooms & Sweep Line
Interval problems appear constantly at Google, Amazon, and Meta — merge overlapping intervals, find minimum meeting rooms, detect gaps, and the sweep line algorithm for complex overlap counting. Covers the sort-then-scan pattern, event-based sweep line, and the priority queue approach for scheduling problems.
The Interval Pattern Family
Interval problems are a family of greedy problems where you're given a set of ranges [start, end] and need to perform operations like merging overlaps, counting simultaneous events, or finding gaps. They appear in scheduling systems, calendar apps, resource allocation, and network packet analysis.
The universal setup: Sort intervals by start time. After sorting, you can scan left to right and make locally optimal decisions (compare current interval's end with the next interval's start) that are globally optimal. Sorting by start time is almost always step 1.
Recognition signals: "intervals", "overlapping", "meeting rooms", "schedule", "merge", "insert and merge", "minimum resources", "free slots".