Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:14:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<v[x].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:22:37: 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:23:39: 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); ^