Compilare: user.cpp: In function ‘bool get_hamiltonian_queries()’: user.cpp:190:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < road.size(); i++) ^ user.cpp: In function ‘bool solve_hamiltonian_query(const hamiltonian_query&)’: user.cpp:238:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < nodes.size(); i++) ^ user.cpp:292:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < nodes.size(); i++) ^ user.cpp:254:9: warning: unused variable ‘j’ [-Wunused-variable] int j; ^ user.cpp: In function ‘bool solve_hamiltonian_queries()’: user.cpp:303:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < queries.size(); i++) ^ user.cpp: In function ‘void print_solution()’: user.cpp:347:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < solution.size(); i++) ^