Method minMeetingRooms

java/0253-meeting-rooms-ii.java:18–40

@param intervals: an array of meeting time intervals @return: the minimum number of conference rooms required

(List<Interval> intervals)

     * @return: the minimum number of conference rooms required
     */
    public int minMeetingRooms(List<Interval> intervals) {
        if (intervals.isEmpty()) return 0;

        Collections.sort(
            intervals,
            (a, b) -> Integer.compare(a.start, b.start)
        );

        Queue<Interval> queue = new PriorityQueue<>((a, b) ->
            Integer.compare(a.end, b.end)
        );

        int count = 0;
        for (Interval interval : intervals) {
            while (
                !queue.isEmpty() && interval.start >= queue.peek().end
            ) queue.poll();

            queue.offer(interval);
            count = Math.max(count, queue.size());
        }
        return count;
    }
}

// Two pointer approach