Practice Design Twitter

Read the task, work through the examples, and check your approach against the constraints. Use the original LeetCode task for coding and submissions.

Medium#355

LeetCode Problem

Design Twitter

Hash Table Linked List Design Heap (Priority Queue)

Problem Statement

Twitter supports postTweet(userId,tweetId), follow(followerId,followeeId), unfollow(followerId,followeeId), and getNewsFeed(userId). A feed contains up to ten latest tweet IDs from the user and currently followed users, newest first. Tweet IDs are unique; posting order, not ID magnitude, defines recency. Practice approach: Store follow sets and per-user timestamped tweet lists. Merge the latest entries of eligible lists with a max-heap until ten tweets are collected. A user's own tweets must remain eligible independently of follow relationships. Test an empty feed, unfollowing, and posts made before following.

Source: Design Twitter on LeetCode. Use the original task for its coding environment and submissions.

Examples

# Example 1

Input

["Twitter","postTweet","postTweet","follow","getNewsFeed","unfollow","getNewsFeed"]
[[],[1,20],[2,10],[1,2],[1],[1,2],[1]]

Output

[null,null,null,null,[10,20],null,[20]]

Explanation

Tweet 10 is newer despite its smaller ID. Unfollowing user 2 removes it from user 1's feed.

Constraints

1 <= user IDs <= 500

0 <= tweetId <= 10^4

Tweet IDs are unique.

At most 3 * 10^4 total method calls.

Users cannot follow themselves.

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