Compilare: user.cpp: In function ‘void dfs(int)’: user.cpp:22:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0; j<v[S].size(); j++) ^ user.cpp: In function ‘int main()’: user.cpp:64:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (ii=0; ii<v[last].size(); ii++) ^ user.cpp:34:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("biperm.in","r",stdin); ^ user.cpp:35:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("biperm.out","w",stdout); ^ user.cpp:39:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d",&n); ^ user.cpp:43:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d",&u[i].a); ^ user.cpp:48:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d",&u[i].b); ^