Compilare: user.cpp: In function ‘void bfs()’: user.cpp:42:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<G[x].size(); ++i) ^ user.cpp:47:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<G[a].size(); ++j) ^ user.cpp:64:54: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int k=0; k<G[b].size(); ++k) ^ user.cpp: In function ‘void out()’: user.cpp:90:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<sol.size(); ++i) ^