UVA 814 The Letter Carrier's Rounds

题目链接：https://vjudge.net/problem/UVA-814

题目翻译摘自《算法禁赛入门经典》

题目大意

　　本题的任务为模拟发送邮件时 MTA（邮件传输代理）之间的交互。所谓 MTA，就是 email地址格式 user@mtaname 的“后面部分”。当某人从 user1@mta1 发送给另一个人 user2@mta2 时，这两个 MTA 将会通信。如果两个收件人属于同一个 MTA，发送者的 MTA 只需与这个 MTA 通信一次就可以把邮件发送给这两个人。

　　输入每个 MTA 里的用户列表，对于每个发送请求（输入发送者和接收者列表），按顺序输出所有 MTA 之间的 SMTP（简单邮件协议）交互。协议细节参见原题。

　　发送人 MTA 连接收件人 MTA 的顺序应该与在输入中第一次出现的顺序一致。

　　如果连接某个 MTA 之后发现所有收件人都不存在，则不应该发送DATA。所有用户名均 由不超过15个字母和数字组成。

　　发信人一定存在。

分析

　　略。

代码如下

#include <bits/stdc++.h>
using namespace std;
 
#define INIT() ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define Rep(i,n) for (int i = 0; i < (n); ++i)
#define For(i,s,t) for (int i = (s); i <= (t); ++i)
#define rFor(i,t,s) for (int i = (t); i >= (s); --i)
#define ForLL(i, s, t) for (LL i = LL(s); i <= LL(t); ++i)
#define rForLL(i, t, s) for (LL i = LL(t); i >= LL(s); --i)
#define foreach(i,c) for (__typeof(c.begin()) i = c.begin(); i != c.end(); ++i)
#define rforeach(i,c) for (__typeof(c.rbegin()) i = c.rbegin(); i != c.rend(); ++i)
 
#define pr(x) cout << #x << " = " << x << "  "
#define prln(x) cout << #x << " = " << x << endl
 
#define LOWBIT(x) ((x)&(-x))
 
#define ALL(x) x.begin(),x.end()
#define INS(x) inserter(x,x.begin())
 
#define ms0(a) memset(a,0,sizeof(a))
#define msI(a) memset(a,inf,sizeof(a))
#define msM(a) memset(a,-1,sizeof(a))

#define MP make_pair
#define PB push_back
#define ft first
#define sd second
 
template<typename T1, typename T2>
istream &operator>>(istream &in, pair<T1, T2> &p) {
    in >> p.first >> p.second;
    return in;
}
 
template<typename T>
istream &operator>>(istream &in, vector<T> &v) {
    for (auto &x: v)
        in >> x;
    return in;
}
 
template<typename T1, typename T2>
ostream &operator<<(ostream &out, const std::pair<T1, T2> &p) {
    out << "[" << p.first << ", " << p.second << "]" << "\n";
    return out;
}

inline int gc(){
    static const int BUF = 1e7;
    static char buf[BUF], *bg = buf + BUF, *ed = bg;
    
    if(bg == ed) fread(bg = buf, 1, BUF, stdin);
    return *bg++;
} 

inline int ri(){
    int x = 0, f = 1, c = gc();
    for(; c<48||c>57; f = c=='-'?-1:f, c=gc());
    for(; c>47&&c<58; x = x*10 + c - 48, c=gc());
    return x*f;
}

template<class T>
inline string toString(T x) {
    ostringstream sout;
    sout << x;
    return sout.str();
}

inline int toInt(string s) {
    int v;
    istringstream sin(s);
    sin >> v;
    return v;
}
 
typedef long long LL;
typedef unsigned long long uLL;
typedef pair< double, double > PDD;
typedef pair< int, int > PII;
typedef pair< int, PII > PIPII;
typedef pair< string, int > PSI;
typedef pair< int, PSI > PIPSI;
typedef set< int > SI;
typedef set< PII > SPII;
typedef vector< int > VI;
typedef vector< VI > VVI;
typedef vector< SI > VSI;
typedef vector< PII > VPII;
typedef map< int, int > MII;
typedef map< int, string > MIS;
typedef map< int, PII > MIPII;
typedef map< PII, int > MPIII;
typedef map< string, int > MSI;
typedef map< string, string > MSS;
typedef map< PII, string > MPIIS;
typedef map< PII, PII > MPIIPII;
typedef multimap< int, int > MMII;
typedef multimap< string, int > MMSI;
//typedef unordered_map< int, int > uMII;
typedef pair< LL, LL > PLL;
typedef vector< LL > VL;
typedef vector< VL > VVL;
typedef priority_queue< int > PQIMax;
typedef priority_queue< int, VI, greater< int > > PQIMin;
const double EPS = 1e-8;
const LL inf = 0x7fffffff;
const LL infLL = 0x7fffffffffffffffLL;
const LL mod = 1e9 + 7;
const int maxN = 1e4 + 7;
const LL ONE = 1;
const LL evenBits = 0xaaaaaaaaaaaaaaaa;
const LL oddBits = 0x5555555555555555;

struct User{
    string mail, name, addr;
    
    User() {}
    User(string s) {
        mail = s;
        name = s.substr(0, s.find('@'));
        addr = s.substr(s.find('@') + 1);
    }
};

MSS mta; // name->address 

int main(){
    //freopen("MyOutput.txt","w",stdout);
    //freopen("input.txt","r",stdin);
    //INIT();
    string tmp, msg;
    while(cin >> tmp) {
        if(tmp == "*") break;
        string loc;
        int n;
        
        cin >> loc >> n;
        Rep(i, n) {
            cin >> tmp;
            mta[tmp] = loc;
        }
    }
    
    while(cin >> tmp) {
        if(tmp == "*") break;
        User from(tmp);
        vector< User > to;
        map< string, VI > msv; // 顺序存相同地址的人 
        set< string > names; // 判重用 
        
        while(cin >> tmp) {
            if(tmp == "*") break;
            User t(tmp);
            
            if(names.find(t.name) != names.end()) continue;
            else names.insert(t.name);
            to.PB(t);
            msv[t.addr].PB(to.size() - 1);
        }
        
        getline(cin, msg); // '\n'
        while(getline(cin, tmp)) {
            if(tmp == "*") break;
            msg += "     " + tmp + "\n";
        }
        
        foreach(i, to) {
            if(msv.find(i->addr) != msv.end()) {
                printf("Connection between %s and %s\n", from.addr.c_str(), i->addr.c_str());
                printf("     HELO %s\n", from.addr.c_str());
                printf("     250\n");
                printf("     MAIL FROM:<%s>\n", from.mail.c_str());
                printf("     250\n");
                
                int cnt = 0;
                foreach(j, msv[i->addr]) {
                    printf("     RCPT TO:<%s>\n", to[*j].mail.c_str());
                    if(mta.find(to[*j].name) != mta.end()) printf("     250\n"), ++cnt;
                    else printf("     550\n");
                }
                msv.erase(i->addr);
                
                if(cnt) {
                    printf("     DATA\n");
                    printf("     354\n");
                    printf("%s", msg.c_str());
                    printf("     .\n");
                    printf("     250\n");
                }
                
                printf("     QUIT\n");
                printf("     221\n");
            }
        }
    }
    return 0;
}