Meeting Rooms II

/**
 * Definition for an interval.
 * public class Interval {
 *     int start;
 *     int end;
 *     Interval() { start = 0; end = 0; }
 *     Interval(int s, int e) { start = s; end = e; }
 * }
 */
public class Solution {
    public int minMeetingRooms(Interval[] intervals) {
        if (intervals.length < 2) {
            return intervals.length;
        }
        
        Arrays.sort(intervals, new Comparator<Interval>() {
            @Override
            public int compare(Interval a, Interval b) {
                return a.start - b.start;
            }
        });
        
        PriorityQueue<Interval> queue = new PriorityQueue<>(intervals.length, new Comparator<Interval>() {
           @Override
           public int compare(Interval a, Interval b) {
               return a.end - b.end;
           }
        });
        
        queue.offer(intervals[0]);
        for (int i = 1; i < intervals.length; i++) {
            Interval current = queue.poll();
            if (intervals[i].start >= current.end) {
                current.end = intervals[i].end;
            } else {
                queue.offer(intervals[i]);
            }
            queue.offer(current);
        }
        return queue.size();
    }
}