algebra_1

#include <stdio.h>
#include <stack>
#include <math.h>
#include <time.h>
#include <iostream>
#include <algorithm>
#include <string>
#include <set>
#include <iomanip>
#include <vector>
#include <map>
#include <cassert>
#include <queue>
#include <fstream>

using namespace std;

typedef long long li;
typedef long double ld;

#define forn(i, n) for (int i = 0; i < int(n); ++i)
#define pb push_back
#define mp make_pair
#define all(v) v.begin(),v.end()
#define EPS 1e-9
#define PI 3.1415926535897932384626433832795


int main () {
    ifstream key_stream("key.txt");
    ifstream text_stream("text.txt");
    freopen("output.txt", "w", stdout);
    string alph = "абвгдезжиклмнопрстуфцчхшщьъэюя0123456789!,.?", key = "";
    bool contain_in_alph[44];
    forn (i, alph.size())
        contain_in_alph[i] = false;
    while (!key_stream.eof()) {
        string temp;
        key_stream >> temp;
        forn (i, temp.size()) {
            temp[i] += (temp[i] >= 'A' && temp[i] <= 'Я') ? ('а' - 'А') : 0;
            int idx = alph.find(temp[i]);
            if (!contain_in_alph[idx])
                contain_in_alph[idx] = true, key += temp[i];
        }
    }
    if (key.size() < alph.size() / 2) {
        cout << "Ключ некорректен" << endl;
        return 0;
    }
    forn (i, alph.size())
        if (!contain_in_alph[i])
            key += alph[i], contain_in_alph[i] = true;

    string result = "";
    while (!text_stream.eof()) {
        string temp;
        text_stream >> temp;
        forn (i, temp.size()) {
            bool fl = false;
            if (temp[i] >= 'А' && temp[i] <= 'Я') {
                temp[i] += 'а' - 'А';
                fl = !fl;
            }
            int idx = key.find(temp[i]);
            result += (key[(idx + (key.size() / 2)) % key.size()] - ((fl) ? ('а' - 'А') : 0));
        }
        result += " ";
    }
    cout << result << endl;

    return 0;
}