814 - The Letter Carrier's Rounds

最新推荐文章于 2023-10-19 11:57:38 发布

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本文介绍了一个邮件路由模拟程序，该程序能够解析电子邮件地址，并通过模拟邮件发送过程来验证目标邮箱的有效性。程序首先读取发件人邮箱地址及收件人列表，然后检查每个收件人的邮箱地址是否有效。

#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;
}