void makeTrail(std::ofstream& ofs, const int& amountOfVertices) {
    size_t* verticesArr = new size_t[amountOfVertices];
    for (size_t i = 0; i < amountOfVertices; ++i)
        verticesArr[i] = i;
    for (size_t j = 0; j < amountOfVertices; ++j) { // shuffle elements in the array
        size_t randomPos = randomGenerator(0, amountOfVertices);
        size_t tempVal = verticesArr[j];
        verticesArr[j] = verticesArr[randomPos];
        verticesArr[randomPos] = tempVal;
    }
    for (size_t k = 0; k < amountOfVertices; ++++k) {
        ofs << verticesArr[k] << ' ' << verticesArr[k + 1] << std::endl;
    }
    delete[]verticesArr;
}