Package g0301_0400.s0355_design_twitter

Class Twitter

java.lang.Object
g0301_0400.s0355_design_twitter.Twitter
public class Twitter extends Object
355 - Design Twitter\. Medium Design a simplified version of Twitter where users can post tweets, follow/unfollow another user, and is able to see the `10` most recent tweets in the user's news feed. Implement the `Twitter` class: * `Twitter()` Initializes your twitter object. * `void postTweet(int userId, int tweetId)` Composes a new tweet with ID `tweetId` by the user `userId`. Each call to this function will be made with a unique `tweetId`. * `List getNewsFeed(int userId)` Retrieves the `10` most recent tweet IDs in the user's news feed. Each item in the news feed must be posted by users who the user followed or by the user themself. Tweets must be **ordered from most recent to least recent**. * `void follow(int followerId, int followeeId)` The user with ID `followerId` started following the user with ID `followeeId`. * `void unfollow(int followerId, int followeeId)` The user with ID `followerId` started unfollowing the user with ID `followeeId`. **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]. return [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]. // Tweet id 6 should precede tweet id 5 because it is posted after tweet id 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], since user 1 is no longer following user 2. **Constraints:** * `1 <= userId, followerId, followeeId <= 500` * 0 <= tweetId <= 104 * All the tweets have **unique** IDs. * At most 3 * 104 calls will be made to `postTweet`, `getNewsFeed`, `follow`, and `unfollow`.

  • Constructor Details

    • Twitter

      public Twitter()

  • Method Details

    • postTweet

      public void postTweet(int userId, int tweetId)

    • getNewsFeed

      public List<Integer> getNewsFeed(int userId)

    • follow

      public void follow(int followerId, int followeeId)

    • unfollow

      public void unfollow(int followerId, int followeeId)

    • checkNewUser

      public void checkNewUser(int userId)