253. 会议室 II

253. 会议室 II

这道题主要考核的是最小堆！！！

class Solution {
public int minMeetingRooms(int[][] intervals) {
        if(intervals == null || intervals.length == 0) return 0;
        Arrays.sort(intervals, (e1,e2)->{
            return e1[0]-e2[0];
        });
        PriorityQueue<Integer> priorityQueue = new PriorityQueue<>();
        for (int i = 0 ; i < intervals.length; i++) {
            priorityQueue.add(intervals[i][1]);
            if(intervals[i][0] >= priorityQueue.peek()) {
                priorityQueue.poll();
            }
        }
        return priorityQueue.size();
    }

}