include <iostream>
#include <string>
#include <thread>
#include <vector>

void culc(std::string* s1, int begin, int end) {
  for (int i = begin; i < end; i++) {
    (*s1)[i] = 'a' + ((*s1)[i] + 3 - 'a') % 26;
  }
}

void CaesarEncrypt(std::string* s) {
  std::thread thread;
  int k = 1;
  int k1 = 2;
  std::vector<std::thread*> threads;
  int N = thread.hardware_concurrency();
  auto tr = new std::thread(culc, std::ref(s), 0, s->size() / N);
  threads.push_back(tr);
  for (int i = 0; i < N - 1; i++) {
    if (i == N - 2) {
      auto t = new std::thread(culc, std::ref(s), s->size() / N * k, s->size());
      threads.push_back(t);
    } else {
      auto t = new std::thread(culc, std::ref(s), s->size() / N * k,
                               s->size() / N * k1);
      k1++;
      k++;
      threads.push_back(t);
    }
  }
  for (int i = 0; i < N; i++) {
    std::cout << threads[i]->get_id() << std::endl;
    threads[i]->join();
  }
}