class MTPGraph {
void initialize_positivized_lengths_with_min();
void update_positivized_lengths();
void force_positivized_lengths();
void find_shortest_path(Vertex **front, Vertex **new_front);
class MTPGraph {
void initialize_positivized_lengths_with_min();
void update_positivized_lengths();
void force_positivized_lengths();
void find_shortest_path(Vertex **front, Vertex **new_front);
MTPGraph(int nb_vertices, int nb_edges, int *from, int *to,
int source, int sink);
~MTPGraph();
MTPGraph(int nb_vertices, int nb_edges, int *from, int *to,
int source, int sink);
~MTPGraph();