Meeting Rooms II

Author: TonyKim9401

meeting-rooms-ii/TonyKim9401.java

@@ -0,0 +1,22 @@
+// TC: O(n)
+// visit all intervals to compare each of start time
+// SC: O(n)
+// PQ save all intervals in the worst case
+public class Solution {
+    public int minMeetingRooms(List<Interval> intervals) {
+        if (intervals == null || intervals.isEmpty()) return 0;
+
+        intervals.sort((a, b) -> a.start - b.start);
+
+        PriorityQueue<Integer> endTimes = new PriorityQueue<>();
+        endTimes.add(intervals.get(0).end);
+
+        for (int i = 1; i < intervals.size(); i++) {
+            Interval current = intervals.get(i);
+            if (current.start >= endTimes.peek()) endTimes.poll();
+            endTimes.add(current.end);
+        }
+
+        return endTimes.size();
+    }
+}