Meeting rooms

Given meeting times, find the minimum number of rooms needed so no two meetings in a room overlap.

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import heapq
def min_rooms(intervals):
    intervals.sort()
    ends = []                                  # min-heap of room end times
    for s, e in intervals:
        if ends and ends[0] <= s: heapq.heapreplace(ends, e)   # reuse
        else: heapq.heappush(ends, e)                          # new room
    return len(ends)