Compilare: user.cpp: In function ‘nod* delete_min(nod*)’: user.cpp:24:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < all.size(); i += 2){ ^ user.cpp:25:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i+1 < all.size()) tmp.push_back(merge_nods(all[i], all[i+1])); ^