zoukankan      html  css  js  c++  java
  • leetcode 355 Design Twitter

    class Twitter {
        unordered_map<int,deque<pair<int,int>>> uid_tid;//deque is double-ended queue
        unordered_map<int,unordered_set<int>> uid_fid;
        int times=0;public:
        /** Initialize your data structure here. */
        Twitter() {
            
        }
        
        /** Compose a new tweet. */
        void postTweet(int userId, int tweetId) {
            if(uid_tid[userId].size()==10) uid_tid[userId].pop_front();
            uid_tid[userId].push_back({tweetId,times++});
        }
        
        /** Retrieve 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 herself. Tweets must be ordered from most recent to least recent. */
        vector<int> getNewsFeed(int userId) {
            vector<pair<int,int>> vec(uid_tid[userId].begin(),uid_tid[userId].end());
            for(auto follow:uid_fid[userId]) {
                vec.insert(vec.end(),uid_tid[follow].begin(),uid_tid[follow].end());
            }
            sort(vec.begin(),vec.end(),[](pair<int,int>&a,pair<int,int>&b){return a.second>b.second;});
            vector<int> re;
            int size=vec.size()<10?vec.size():10;
            for(int i=0;i<size;++i) {
                re.push_back(vec[i].first);
            }
            return re;
        }
        
        /** Follower follows a followee. If the operation is invalid, it should be a no-op. */
        void follow(int followerId, int followeeId) {
            if(followerId==followeeId) return;
            if(uid_fid[followerId].find(followeeId)!=uid_fid[followerId].end()) return;
            uid_fid[followerId].insert(followeeId);
        }
        
        /** Follower unfollows a followee. If the operation is invalid, it should be a no-op. */
        void unfollow(int followerId, int followeeId) {
            uid_fid[followerId].erase(followeeId);
        }
    };
    
    /**
     * Your Twitter object will be instantiated and called as such:
     * Twitter* obj = new Twitter();
     * obj->postTweet(userId,tweetId);
     * vector<int> param_2 = obj->getNewsFeed(userId);
     * obj->follow(followerId,followeeId);
     * obj->unfollow(followerId,followeeId);
     */
  • 相关阅读:
    生手和FinallyJane一起学习ASP.NET
    使用eclipse 初学java
    关于C#中用access做数据库,使用like语句的问题(转)
    VSS (Visual Source Safe 2005) 用法详解(转)
    mysql 字符集问题之我见
    mysqli的预处理功能使用
    兼容IE和Firefox
    linux下netsnmp 已经安装,为什么没有 snmpwalk和snmpget
    ? PHP WBEM
    安装cacti时提示错误
  • 原文地址:https://www.cnblogs.com/LiuQiujie/p/12596791.html
Copyright © 2011-2022 走看看