solve: meeting-rooms-ii

Author: sounmind

meeting-rooms-ii/evan.py

@@ -0,0 +1,39 @@
+from typing import List
+
+
+# Definition of Interval:
+class Interval(object):
+    def __init__(self, start, end):
+        self.start = start
+        self.end = end
+
+
+class Solution:
+    """
+    @param intervals: an array of meeting time intervals
+    @return: the minimum number of conference rooms required
+    """
+
+    def min_meeting_rooms(self, intervals: List[Interval]) -> int:
+        if not intervals:
+            return 0
+
+        start_times = sorted([i.start for i in intervals])
+        end_times = sorted([i.end for i in intervals])
+
+        start_pointer, end_pointer = 0, 0
+        used_rooms = 0
+
+        while start_pointer < len(intervals):
+            # If there is a meeting that has ended by the time the meeting at `start_pointer` starts
+            if start_times[start_pointer] >= end_times[end_pointer]:
+                used_rooms -= 1
+                end_pointer += 1
+
+            # We do this irrespective of whether a room frees up or not.
+            # If a room got free, then this used_rooms += 1 wouldn't have any effect.
+            # used_rooms would remain the same in that case.
+            used_rooms += 1
+            start_pointer += 1
+
+        return used_rooms