Compilare: main.cpp: In function 'void df(int)': main.cpp:12:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<v[x].size();i++) ~^~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:46:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<s.size();i++){out<<s[i].first<<" "<<s[i].second<<'\n';} ~^~~~~~~~~