Compilare: user.cpp: In function ‘int main()’: user.cpp:24:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0; j<v[q.front()].size(); ++j) ^ user.cpp:12:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bfs.in","r",stdin); ^ user.cpp:13:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bfs.out","w",stdout); ^ user.cpp:14:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&n,&m,&t); ^ user.cpp:17:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&a,&b); ^