Compilare: main.cpp: In function 'void Prim()': main.cpp:26:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0 ; i < v[nod].size() ; ++i) ~~^~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:47:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < sol.size() ; ++i) g << sol[i].first << ' ' << sol[i].second << '\n' ; ~~^~~~~~~~~~~~