LeetCode - Meeting Rooms II

Given an array of meeting time intervals consisting of start and end times [[s1,e1],[s2,e2],...] (si < ei), find the minimum number of conference rooms required.

Example 1:

Input: [[0, 30],[5, 10],[15, 20]]
Output: 2

Example 2:

Input: [[7,10],[2,4]]
Output: 1

Java Solution :

class Solution {
    public int minMeetingRooms(int[][] intervals) {
        Arrays.sort(intervals,(a,b)-> a[0] - b[0]);
        int numOfMeetingRooms = 0;
PriorityQueue<Integer> minHeap = new PriorityQueue<>();        
        for(int[] interval : intervals){
            if(minHeap.isEmpty()){
                minHeap.offer(interval[1]);
                numOfMeetingRooms++;
            }else if(minHeap.peek() <= interval[0]){
                minHeap.poll();
                minHeap.offer(interval[1]);
            }else{
                minHeap.offer(interval[1]);
                numOfMeetingRooms++;
            }
        }
       return numOfMeetingRooms;
    }
}