Compilare: user.cpp: In function ‘void bfs(int, int)’: user.cpp:27:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0; j<v[x].size(); j++) ^ user.cpp: In function ‘int main()’: user.cpp:42:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("marmelada.in","r",stdin); ^ user.cpp:43:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("marmelada.out","w",stdout); ^ user.cpp:46:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d %d %d",&n,&m,&s,&d); ^ user.cpp:51:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d",&a,&b); ^ user.cpp:60:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d",&l[i]); ^