Compilare: user.cpp: In function ‘bool bfs()’: user.cpp:44:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<gr[vf].size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:100:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<gr[d].size();i++) ^ user.cpp:136:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<gr[n+i].size();j++) ^