814 - The Letter Carrier's Rounds

#include<iostream>
#include<algorithm>
#include<map>
#include<set>
#include<vector>
using namespace std;
void parse_address(const string& s, string &user,string &mta) {
    int k = s.find('@');
    user = s.substr(0,k);
    mta=s.substr(k+1);
}
int main() {
    int k;
    string s,t,user1,mta1,user2,mta2;
    set<string> addr;

    while(cin>>s && s!="*") {
        cin>>s>>k;
        while(k--) { cin>>t;addr.insert(t+"@"+s) ; }   //addr存放第一个表
    }
    while(cin>>s&&s!="*") {
        parse_address(s, user1, mta1); //存放发件人
        vector<string>mta;//存放mta;
        map<string,vector<string> > dest;
        set<string> vis;  //存放收件人
        while(cin>>t&&t!="*") {
            parse_address(t,user2,mta2);
            if(vis.count(t)) continue;
            vis.insert(t);
            if(!dest.count(mta2)) { mta.push_back(mta2);dest[mta2]=vector<string>(); }
            dest[mta2].push_back(t); //无论收件人是否重复，都存进映射；
        }
        getline(cin,t);
        string data;
        while(getline(cin,t)&&t[0]!='*') data+="     "+t+"\n";
        for(int i=0;i<mta.size();i++) {
            string mta2 = mta[i];
            vector<string> users=dest[mta2];
            cout<<"Connection between "<<mta1<<" and "<<mta2<<endl;
            cout<<"     HELO "<<mta1<<"\n"; cout<<"     250\n";
            cout<<"     MAIL FROM:<"<<user1+"@"+mta1<<">\n"; cout<<"     250\n";
            bool ok =false;
            for(int i=0;i<users.size();i++) {
                cout<<"     RCPT TO:<"<<users[i]<<">\n";
                if(addr.count(users[i])) { ok=true; cout<<"     250\n"; }
                else cout<<"     550\n";
            }
               if(ok) {
                    cout<<"     DATA\n"; cout<<"     354\n";
                    cout<< data;
                    cout<<"     .\n"; cout<<"     250\n";
               }
                cout<<"     QUIT\n"; cout<<"     221\n";
        }
    }
    return 0;
}