Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:28:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v[nod].size (); ++i) { ^ user.cpp:40:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < v[nod].size (); ++i) { ^ user.cpp: In function ‘int main()’: user.cpp:53:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("arb2.in", "r", stdin); ^ user.cpp:54:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("arb2.out", "w", stdout); ^ user.cpp:57:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d", &n); ^ user.cpp:59:43: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d%d%d", &x, &y, &d, &c); ^