Compilare: user.cpp: In function ‘void bfs()’: user.cpp:17:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k = 0; k < q.size(); ++k){ ^ user.cpp:19:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < g1[now].size(); ++i)if(!vis[g1[now][i]]){ ^ user.cpp:25:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k = 0; k < q.size(); ++k){ ^ user.cpp:27:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < g2[now].size(); ++i)if(!vis[g2[now][i]]){ ^