Implement Posting and Follow-Based Recent Tweet Feeds
Company: Google
Role: Software Engineer
Category: Coding & Algorithms
Difficulty: medium
Interview Round: Other
### Problem
Implement Twitter with postTweet, getNewsFeed, follow and unfollow. A feed contains at most ten most recent tweet IDs posted by the user or their currently followed users, newest first. Tweet IDs are unique identifiers, not chronological values. Follow/unfollow alter whose stored tweets are eligible; preserve all constructor and method signatures.
```cpp
class Twitter {
public:
Twitter();
void postTweet(int userId, int tweetId);
vector<int> getNewsFeed(int userId);
void follow(int followerId, int followeeId);
void unfollow(int followerId, int followeeId);
};
```
### Examples
```text
Twitter(); postTweet(1,8); follow(1,2); postTweet(2,3); getNewsFeed(1) -> [3,8]; unfollow(1,2); getNewsFeed(1) -> [8]
Twitter(); getNewsFeed(4) -> []
```
### Constraints
- User/follower/followee IDs lie in [1,500].
- Tweet IDs lie in [0,10000] and all posted IDs are unique.
- At most 30000 total method calls occur.
- A user cannot follow themself.
Overview: Implement Posting and Follow-Based Recent Tweet Feeds. Implement Twitter with postTweet, getNewsFeed, follow and unfollow. A feed contains at most ten most recent tweet IDs posted by the user or their currently foll