Design a Twitter

Write a C++ program to design a Twitter-like timeline system that supports posting tweets, retrieving news feeds, following and unfollowing users.

Example 1

  
Input: ["Twitter", "postTweet", "getNewsFeed", "follow", "postTweet", "getNewsFeed", "unfollow", "getNewsFeed"]
[[], [1, 5], [1], [1, 2], [2, 6], [1], [1, 2], [1]]
  
Output: [null, null, [5], null, null, [6, 5], null, [5]]
  
Explanation: 

      
Twitter twitter = new Twitter();
      
twitter.postTweet(1, 5); // User 1 posts a new tweet (id = 5)
      
twitter.getNewsFeed(1);  // User 1's news feed should return a list with 1 tweet id -> [5]
      
twitter.follow(1, 2);    // User 1 follows user 2
      
twitter.postTweet(2, 6); // User 2 posts a new tweet (id = 6)
      
twitter.getNewsFeed(1);  // User 1's news feed should return a list with 2 tweet ids -> [6, 5]
      
twitter.unfollow(1, 2);  // User 1 unfollows user 2
      
twitter.getNewsFeed(1);  // User 1's news feed should return a list with 1 tweet id -> [5]
    

Example 2

  
Input: ["Twitter", "postTweet", "postTweet", "postTweet", "follow", "getNewsFeed"]
[[], [1, 10], [1, 11], [2, 12], [1, 2], [1]]
  
Output: [null, null, null, null, null, [12, 11, 10]]
  
Explanation: 

      
Twitter twitter = new Twitter();
      
twitter.postTweet(1, 10); // User 1 posts a new tweet (id = 10)
      
twitter.postTweet(1, 11); // User 1 posts a new tweet (id = 11)
      
twitter.postTweet(2, 12); // User 2 posts a new tweet (id = 12)
      
twitter.follow(1, 2);     // User 1 follows user 2
      
twitter.getNewsFeed(1);   // User 1's news feed should return the 3 tweets -> [12, 11, 10]
    

Constraints

  
1 <= userId, followerId, followeeId <= 500
  
0 <= tweetId <= 10^4
  
All the tweets have unique IDs.
  
At most 3 * 10^4 calls will be made to postTweet, getNewsFeed, follow, and unfollow.
  
Time Complexity: O(N log K) for getNewsFeed operation where N is the total number of tweets and K is the feed size (10)
  
Space Complexity: O(U + E + T) where U is the number of users, E is the number of follow relationships, and T is the number of tweets