Compilare: user.cpp: In function ‘int main()’: user.cpp:8:113: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] int main(){f>>n;for(i=1;i<=n;i++){f>>x;mp[prod(x)].push_back(x);}f>>m;for(i=1;i<=m;i++){f>>x>>y;if(mp[y].size()<x) g<<-1<<"\n";else g<<mp[y][x-1]<<"\n";}return 0;} ^