update 253

Author: fishercoder1534

Diff for: src/main/java/com/fishercoder/solutions/_253.java

@@ -5,67 +5,30 @@
 
 public class _253 {
     public static class Solution1 {
-
         public int minMeetingRooms(int[][] intervals) {
             if (intervals == null || intervals.length == 0) {
                 return 0;
             }
-
-            // Sort the intervals by start time
-            Arrays.sort(intervals, (a, b) -> a[0] - b[0]);
-
-            // Use a min heap to track the minimum end time of merged intervals
-            PriorityQueue<int[]> heap = new PriorityQueue<>(intervals.length, (a, b) -> a[1] - b[1]);
-
-            // start with the first meeting, put it to a meeting room
-            heap.offer(intervals[0]);
-
+            Arrays.sort(intervals, (a, b) -> a[0] - b[0]);// Sort the intervals by start time
+            PriorityQueue<int[]> heap = new PriorityQueue<>(intervals.length, (a, b) -> a[1] - b[1]);// Use a min heap to track the minimum end time of merged intervals
+            heap.offer(intervals[0]);// start with the first meeting, put it to a meeting room
             for (int i = 1; i < intervals.length; i++) {
                 // get the meeting room that finishes earliest
-                int[] interval = heap.poll();
-
-                if (intervals[i][0] >= interval[1]) {
+                int[] last = heap.poll();
+                if (intervals[i][0] >= last[1]) {
                     // if the current meeting starts right after
                     // there's no need for a new room, merge the interval
-                    interval[1] = intervals[i][1];
+                    last[1] = intervals[i][1];
                 } else {
                     // otherwise, this meeting needs a new room
                     heap.offer(intervals[i]);
                 }
-
                 // don't forget to put the meeting room back
-                heap.offer(interval);
+                heap.offer(last);
             }
 
             return heap.size();
         }
     }
-
-    public static class Solution2 {
-        /**
-         * I'm so glad to have come up with this solution completely on my own on 10/13/2021.
-         * Drawing on a piece of paper helps A LOT! It helps visualize your thoughts and clear the ambiguity up!
-         */
-        public int minMeetingRooms(int[][] intervals) {
-            //I use the meeting's end time as the room indicate and put them into a heap
-            PriorityQueue<Integer> rooms = new PriorityQueue<>();
-            Arrays.sort(intervals, (a, b) -> a[0] - b[0]);
-            for (int i = 0; i < intervals.length; i++) {
-                if (rooms.isEmpty()) {
-                    rooms.add(intervals[i][1]);
-                } else {
-                    if (rooms.peek() > intervals[i][0]) {
-                        //if the room that becomes available the earliest still cannot accommodate this new meeting, then we'll have to add a new room
-                        rooms.add(intervals[i][1]);
-                    } else {
-                        //otherwise, we'll just update the room that finishes the earliest with the new finish time.
-                        rooms.poll();
-                        rooms.add(intervals[i][1]);
-                    }
-                }
-            }
-            return rooms.size();
-        }
-    }
 }