Merge Intervals

Sort first, then a single linear sweep. Sort by start to merge; sort by end for greedy "max non-overlapping"; use a min-heap of end times for room/resource…

Insert a new interval into a sorted, non-overlapping list by scanning in three phases—before, merge, after—without full resorting.

After sorting by start time, a person can attend all meetings iff every meeting starts on or after the previous meeting’s end (no overlap).

The minimum number of conference rooms equals the maximum number of meetings happening at the same time; track “active” meetings via a min-heap of end times…

With two sorted, disjoint lists, walk both with two pointers; the intersection of current intervals is [max(starts), min(ends)] when max(starts) <=…