355. Design Twitter Medium

1/**
2 * [355] Design Twitter
3 *
4 * 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.
5 * Implement the Twitter class:
6 * 
7 * 	Twitter() Initializes your twitter object.
8 * 	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.
9 * 	List<Integer> 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.
10 * 	void follow(int followerId, int followeeId) The user with ID followerId started following the user with ID followeeId.
11 * 	void unfollow(int followerId, int followeeId) The user with ID followerId started unfollowing the user with ID followeeId.
12 * 
13 *  
14 * Example 1:
15 * 
16 * Input
17 * ["Twitter", "postTweet", "getNewsFeed", "follow", "postTweet", "getNewsFeed", "unfollow", "getNewsFeed"]
18 * [[], [1, 5], [1], [1, 2], [2, 6], [1], [1, 2], [1]]
19 * Output
20 * [null, null, [5], null, null, [6, 5], null, [5]]
21 * Explanation
22 * Twitter twitter = new Twitter();
23 * twitter.postTweet(1, 5); // User 1 posts a new tweet (id = 5).
24 * twitter.getNewsFeed(1);  // User 1's news feed should return a list with 1 tweet id -> [5]. return [5]
25 * twitter.follow(1, 2);    // User 1 follows user 2.
26 * twitter.postTweet(2, 6); // User 2 posts a new tweet (id = 6).
27 * 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.
28 * twitter.unfollow(1, 2);  // User 1 unfollows user 2.
29 * 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.
30 * 
31 *  
32 * Constraints:
33 * 
34 * 	1 <= userId, followerId, followeeId <= 500
35 * 	0 <= tweetId <= 10^4
36 * 	All the tweets have unique IDs.
37 * 	At most 3 * 10^4 calls will be made to postTweet, getNewsFeed, follow, and unfollow.
38 * 
39 */
40pub struct Solution {}
41
42// problem: https://leetcode.com/problems/design-twitter/
43// discuss: https://leetcode.com/problems/design-twitter/discuss/?currentPage=1&orderBy=most_votes&query=
44
45// submission codes start here
46
47struct Twitter {
48        false
49    }
50
51
52/** 
53 * `&self` means the method takes an immutable reference.
54 * If you need a mutable reference, change it to `&mut self` instead.
55 */
56impl Twitter {
57
58    fn new() -> Self {
59        
60    }
61    
62    fn post_tweet(&self, user_id: i32, tweet_id: i32) {
63        
64    }
65    
66    fn get_news_feed(&self, user_id: i32) -> Vec<i32> {
67        
68    }
69    
70    fn follow(&self, follower_id: i32, followee_id: i32) {
71        
72    }
73    
74    fn unfollow(&self, follower_id: i32, followee_id: i32) {
75        
76    }
77}
78
79/**
80 * Your Twitter object will be instantiated and called as such:
81 * let obj = Twitter::new();
82 * obj.post_tweet(userId, tweetId);
83 * let ret_2: Vec<i32> = obj.get_news_feed(userId);
84 * obj.follow(followerId, followeeId);
85 * obj.unfollow(followerId, followeeId);
86 */
87
88// submission codes end
89
90#[cfg(test)]
91mod tests {
92    use super::*;
93
94    #[test]
95    fn test_355() {
96    }
97}
98