struct graphrec{
  struct vertex *vertices;
  int num_vert;
  int **edges;
};


graph graph_new(int num_vertices){
  graph g = malloc(sizeof *g);
  g->num_vert = num_vertices;
  const size_t row_pointers_bytes = num_vertices * sizeof *g->edges;
  const size_t row_elements_bytes = num_vertices * sizeof **g->edges;
  g->edges = malloc(row_pointers_bytes + num_vertices * row_elements_bytes);
  g->vertices = malloc(num_vertices * sizeof(g->vertices));
  return g;
}

void graph_free(graph g){
  free(g->vertices);
  free(g->edges);
  free(g);