Compilare: user.cpp: In function ‘void read()’: user.cpp:27:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < back[x].size(); j++) ^ user.cpp:30:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < ini_list[y].size(); j++) ^ user.cpp: In function ‘void add_false_vertex()’: user.cpp:40:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (list[i].size() != in_gr[i]){ ^ user.cpp:44:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (list[i].size() > in_gr[i]) list[0].push_back(i), in_gr[i]++; ^