Compilare: user.cpp: In function ‘void bfs(int, int*)’: user.cpp:17:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0; j<v[c[c1]].size(); j++) ^ user.cpp: In function ‘int main()’: user.cpp:32:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("graf.in","r",stdin); ^ user.cpp:33:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("graf.out","w",stdout); ^ user.cpp:36:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d %d %d",&n,&m,&x,&y); ^ user.cpp:41:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d",&a,&b); ^