Compilare: user.cpp: In function ‘void topological_sort(int)’: user.cpp:59:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < fwd[nod].size(); i++) ^ user.cpp: In function ‘void solve(std::vector<int>, std::vector<int>*, int*)’: user.cpp:67:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v.size(); i++) ^ user.cpp:69:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v.size(); i++) ^