Compilare: user.cpp: In function ‘int main()’: user.cpp:34:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[u].size();i++) ~^~~~~~~~~~~~ user.cpp:35:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=i;j<v[u].size();j++) ~^~~~~~~~~~~~ user.cpp:38:32: warning: ‘y’ may be used uninitialized in this function [-Wmaybe-uninitialized] fout<<cnt<<" "<<x<<" "<<y<<"\n"; ^~~~ user.cpp:38:24: warning: ‘x’ may be used uninitialized in this function [-Wmaybe-uninitialized] fout<<cnt<<" "<<x<<" "<<y<<"\n"; ^~~