0355-design-twitter.py

classTwitter:
def__init__(self):
self.count=0
self.tweetMap=defaultdict(list) # userId -> list of [count, tweetIds]
self.followMap=defaultdict(set) # userId -> set of followeeId

defpostTweet(self, userId: int, tweetId: int) ->None:
self.tweetMap[userId].append([self.count, tweetId])
self.count-=1

defgetNewsFeed(self, userId: int) ->List[int]:
res= []
minHeap= []

self.followMap[userId].add(userId)
forfolloweeIdinself.followMap[userId]:
iffolloweeIdinself.tweetMap:
index=len(self.tweetMap[followeeId]) -1
count, tweetId=self.tweetMap[followeeId][index]
heapq.heappush(minHeap, [count, tweetId, followeeId, index-1])

whileminHeapandlen(res) <10:
count, tweetId, followeeId, index=heapq.heappop(minHeap)
res.append(tweetId)
ifindex>=0:
count, tweetId=self.tweetMap[followeeId][index]
heapq.heappush(minHeap, [count, tweetId, followeeId, index-1])
returnres

deffollow(self, followerId: int, followeeId: int) ->None:
self.followMap[followerId].add(followeeId)

defunfollow(self, followerId: int, followeeId: int) ->None:
iffolloweeIdinself.followMap[followerId]:
self.followMap[followerId].remove(followeeId)