Pattern visualizer

Meeting Rooms II

The insight: the number of rooms needed is just the peak number of meetings happening at the same instant — no need to simulate assigning meetings to specific rooms, just track how high the overlap gets. Sorting starts and ends separately and sweeping through them as a timeline of "a meeting began" / "a meeting ended" events does exactly that: whenever a new start arrives before the earliest still-unfinished meeting has ended, that's one more room needed right now; once a start arrives after that earliest end, a room has already freed up and can be reused instead. Starts: [0,5,15], Ends: [10,20,30] — two meetings are already running (started at 0 and 5) before either finishes at 10, so the peak of 2 rooms happens right at the start, and no later start ever needs a third. Animated on: Given an array of intervals representing meeting time ranges, find the minimum number of conference rooms required so that all meetings can be hosted without overlap..