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0355-design-twitter.js
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0355-design-twitter.js
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/**
* https://leetcode.com/problems/design-twitter/
* Your Twitter object will be instantiated and called as such:
* var obj = new Twitter()
* obj.postTweet(userId,tweetId)
* var param_2 = obj.getNewsFeed(userId)
* obj.follow(followerId,followeeId)
* obj.unfollow(followerId,followeeId)
*/
class Twitter {
constructor () {
this.tweets = [];
this.following = new Map();
}
postTweet (userId, tweetId, { tweets } = this) {
tweets.push({ authorId: userId, id: tweetId });
}
getNewsFeed (userId, newsIDs = [], { tweets, following } = this) {
for (let i = (tweets.length - 1); ((0 <= i) && (newsIDs.length < 10)); i--) {
const tweet = tweets[i];
const isAuthor = tweet.authorId === userId
const isFollowing = following?.get(userId)?.has(tweet.authorId);
const canAddTweet = isAuthor || isFollowing
if (canAddTweet) newsIDs.push(tweet.id);
}
return newsIDs;
}
follow (followerId, followeeId, { following } = this) {
if (!following.has(followerId)) following.set(followerId, new Set());
following.get(followerId).add(followeeId);
}
unfollow (followerId, followeeId, { following } = this) {
if (following.has(followerId)) following.get(followerId).delete(followeeId);
}
}