Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:14:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (currentFriend == fr.size()) { ^ user.cpp: In function ‘int main()’: user.cpp:27:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("marvel.in", "r", stdin); ^ user.cpp:28:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("marvel.out", "w", stdout); ^