multimap创建
  multimap<string , string> m;
m.insert(make_pair("12","3234"));
m.insert(make_pair("12","3234"));
m.insert(make_pair("12","3234"));
遍历
    multimap<string , string> m;
m.insert(make_pair("12","3234"));
m.insert(make_pair("12","3234"));
m.insert(make_pair("12","3234"));for (auto x:m){cout<<x.first<<"   "<<x.second<<endl;
}
