Time: 63 ms (32.7%), Space: 18 MB (79.09%) - LeetHub

Author: hogan-tech

3433-count-mentions-per-user/3433-count-mentions-per-user.py

@@ -0,0 +1,64 @@
+# time complexity: O(n^2)
+# space complexity: O(n)
+from typing import List
+
+
+class Solution:
+    def countMentions(self, numberOfUsers: int, events: List[List[str]]) -> List[int]:
+        mentions = [0] * numberOfUsers
+        onlineUsers = set(range(numberOfUsers))
+        offlineUsers = {}
+
+        events.sort(key=lambda x: (int(x[1]), x[0] == "MESSAGE"))
+
+        for event in events:
+            eventType, timestamp, data = event
+            timestamp = int(timestamp)
+
+            usersToRestore = [
+                uid for uid, returnTime in offlineUsers.items() if returnTime <= timestamp]
+            for uid in usersToRestore:
+                onlineUsers.add(uid)
+                del offlineUsers[uid]
+
+            if eventType == "OFFLINE":
+                userId = int(data)
+                onlineUsers.discard(userId)
+                offlineUsers[userId] = timestamp + 60
+
+            elif eventType == "MESSAGE":
+                mentionedUsers = data.split()
+
+                if "ALL" in mentionedUsers:
+                    for user in range(numberOfUsers):
+                        mentions[user] += 1
+
+                elif "HERE" in mentionedUsers:
+                    for user in onlineUsers:
+                        mentions[user] += 1
+
+                else:
+                    for userStr in mentionedUsers:
+                        if userStr.startswith("id"):
+                            userId = int(userStr[2:])
+                            mentions[userId] += 1
+
+        return mentions
+
+
+numberOfUsers = 2
+events = [["MESSAGE", "10", "id1 id0"], [
+    "OFFLINE", "11", "0"], ["MESSAGE", "71", "HERE"]]
+print(Solution().countMentions(numberOfUsers, events))
+numberOfUsers = 2
+events = [["MESSAGE", "10", "id1 id0"], [
+    "OFFLINE", "11", "0"], ["MESSAGE", "12", "ALL"]]
+print(Solution().countMentions(numberOfUsers, events))
+numberOfUsers = 2
+events = [["OFFLINE", "10", "0"], ["MESSAGE", "12", "HERE"]]
+print(Solution().countMentions(numberOfUsers, events))
+numberOfUsers = 3
+events = [["MESSAGE", "2", "HERE"], ["OFFLINE", "2", "1"],
+          ["OFFLINE", "1", "0"], ["MESSAGE", "61", "HERE"]]
+# expect = [1,0,2]
+print(Solution().countMentions(numberOfUsers, events))