Compilare: user.cpp: In function ‘void DFS(int)’: user.cpp:25:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v[node].size(); i++) { ~~^~~~~~~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:56:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pang.in", "r", stdin); ^ user.cpp:57:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("pang.out", "w", stdout); ^