Meeting Rooms / Meeting Rooms II (interval scheduling) with large-input follow-up

Given meeting intervals intervals[i] = [start_i, end_i), return the minimum number of conference rooms required so that no overlapping meetings share the same room. Requirements: Input: n intervals, 1 <= n <= 2 * 10^5 (discuss larger scale in follow-up). Output: minimum number of rooms. Follow-up (very large input): If n is extremely large such that it may not fit in memory, or sorting is the bottleneck, how would you adapt the solution (e.g., streaming, chunking/external sort, I/O optimizations, distributed aggregation)? Example Input 3 0 30 5 10 15 20 Output 2