Compilare: user.cpp: In function ‘void DFS(int)’: user.cpp:11:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < nodes[i].size(); j++) { ^ user.cpp: In function ‘int main()’: user.cpp:20:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.in", "r", stdin); ^ user.cpp:21:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sortaret.out", "w", stdout); ^