Compilare: user.cpp: In function ‘void bfs(int)’: user.cpp:28:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < G[nod].size(); ++i){ ^ user.cpp: In function ‘void form_graph()’: user.cpp:45:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < lin.second.size(); ++i){ ^ user.cpp:59:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < col.second.size(); ++i){ ^