Compilare: user.cpp: In function ‘void BFS(int)’: user.cpp:26:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<gf[s].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:72:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<sol.size(); i++) ^