3433. Count Mentions Per User

Medium

30 Points

Array

Math

Sorting

Simulation

You are given an integer numberOfUsers representing the total number of users and an array events of size n x 3. Each events[i] can be either of the following two types: Return an array mentions where mentions[i] represents the number of mentions the user with id i has across all MESSAGE events. All users are initially online, and if a user goes offline or comes back online, their status change is processed before handling any message event that occurs at the same timestamp. Note that a user can be mentioned multiple times in a single message event, and each mention should be counted separately.

Examples

Example 1

Input: numberOfUsers = 2, events = [["MESSAGE","10","id1 id0"],["OFFLINE","11","0"],["MESSAGE","71","HERE"]] Output: [2,2] Explanation: Initially, all users are online. At timestamp 10, id1 and id0 are mentioned. mentions = [1,1] At timestamp 11, id0 goes offline. At timestamp 71, id0 comes back online and "HERE" is mentioned. mentions = [2,2]

Example 2

Input: numberOfUsers = 2, events = [["MESSAGE","10","id1 id0"],["OFFLINE","11","0"],["MESSAGE","12","ALL"]] Output: [2,2] Explanation: Initially, all users are online. At timestamp 10, id1 and id0 are mentioned. mentions = [1,1] At timestamp 11, id0 goes offline. At timestamp 12, "ALL" is mentioned. This includes offline users, so both id0 and id1 are mentioned. mentions = [2,2]

Example 3

Input: numberOfUsers = 2, events = [["OFFLINE","10","0"],["MESSAGE","12","HERE"]] Output: [0,1] Explanation: Initially, all users are online. At timestamp 10, id0 goes offline. At timestamp 12, "HERE" is mentioned. Because id0 is still offline, they will not be mentioned. mentions = [0,1]

Constraints

1 <= numberOfUsers <= 100
1 <= events.length <= 100
events[i].length == 3
events[i][0] will be one of MESSAGE or OFFLINE.
1 <= int(events[i][1]) <= 105
The number of id<number> mentions in any "MESSAGE" event is between 1 and 100.
0 <= <number> <= numberOfUsers - 1
It is guaranteed that the user id referenced in the OFFLINE event is online at the time the event occurs.