Compilare: user.cpp: In function ‘void Read()’: user.cpp:13:10: warning: unused variable ‘ch’ [-Wunused-variable] char ch; ^ user.cpp: In function ‘void Solve()’: user.cpp:77:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<V[1].size();i++) ^ user.cpp:83:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<V[i].size();j++) ^