终于感觉到一个简单的题
#include<iostream>
#include<string>
#include<vector>
#include<set>
#include<map>
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); }
}
while(cin>>s&&s!="*"){
parse_address(s, user1, mta1);
vector<string> mta;
map<string, vector<string> >dest;
set<string> vis;
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);
}
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:<"<<s<<">\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;
}