邮件传输代理的交互 The Letter Carrier‘s Rounds

题目

#define _CRT_SECURE_NO_WARNINGS
#define LOCAL 1
#include <iostream>
#include <set>
#include <map>
#include <string>
#include <vector>
#include <algorithm>

using namespace std;

void parse_address(const string& s, string& user, string& mta) { //将完整的邮件提取用户名和地址
	int k = s.find('@');
	user = s.substr(0, k);
	mta = s.substr(k + 1);
}
int main()
{
#ifdef LOCAL
	freopen("C:/Users/pyliu/代码/Visual stdio/语言篇/STL入门/竞赛题目/邮件传输代理的交互 The Letter Carrier's Rounds/input.txt", "r", stdin); 
	freopen("C:/Users/pyliu/代码/Visual stdio/语言篇/STL入门/竞赛题目/邮件传输代理的交互 The Letter Carrier's Rounds/output.txt", "w", stdout);
#endif // LOCAL

	int k;
	string s, t, user1, user2, mta1, mta2;
	set<string> addr;//存放完整的用户邮箱
	while (cin >> s && s != "*") {    //读取地址 及 包含的用户 此处s读取为MTA
		cin >> s >> k; //地址s有k个用户
		while (k--) { cin >> t; addr.insert(t + "@" + s); }
	}
	while (cin >> s && s != "*") { //多次处理发件人
		parse_address(s, user1, mta1); //发件人的username 和mta
		/*	需要收件人的完整邮箱判断是否有重复收件人 set<string>
		*	需要mta输出顺序 vector<string>
		*	需要每个mta对应的收件人邮箱	map<string,vector<string>>
		*	根据mta输出顺序找到其对应的收件人的全部邮箱，再判断是否输出
		*/
		vector<string> mta;
		set<string> vis; 
		map<string, vector<string>> dest;
		while (cin >> t && t != "*") { //处理多个收件人
			parse_address(t, user2, mta2); //收件人的username 和mta
			if (vis.count(t)) continue;
			vis.insert(t);
			if (!dest.count(mta2)) {
				dest[mta2] = vector<string>();
				mta.push_back(mta2);
			}
			dest[mta2].push_back(t);
		}
		//由于正文要读取一整行，用getline函数,因此需要将*和回车吃掉
		getline(cin, t);
		string data;
		while (getline(cin, t) && t != "*") { //正文读取
			data += "     " + t + "\n";
		}
		for (int i = 0; i < mta.size(); i++) { //数据输出
			mta2 = mta[i]; //收件地址
			vector<string> users = dest[mta2];//收件姓名
			cout << "Connection between " << mta1 << " and " << mta2 << endl;
			cout << "     HELO " << mta1 << endl << "     250" << endl;
			cout << "     MAIL FROM:<" << s << ">\n" << "     250" << endl;
			bool flag = false;//判断最后是否有正确的收件人
			for (int j = 0; j < users.size(); j++) {
				cout << "     RCPT TO:<" << users[j] << ">" << endl;
				if (addr.count(users[j])) { cout << "     250" << endl; flag = true; }
				else cout << "     550" << endl;
			}
			if (flag) { 
				cout << "     DATA\n" << "     354\n";
				cout << data << "     .\n     250\n";
			}
			cout<<"     QUIT\n     221\n";
		}
	}
	return 0;
}