/in/foo.cc: In function 'void hash(ull)':
/in/foo.cc:13:18: error: reference to 'next' is ambiguous
  ver[++tot]=now; next[tot]=head[x]; head[x]=tot;
                  ^~~~
/in/foo.cc:7:33: note: candidates are: int next [1000010]
 int a[1010][1010],head[1000010],next[1000010],n,m,q,tot,r,c,i,j,k;
                                 ^~~~
In file included from /usr/include/c++/6/bits/stl_algobase.h:66:0,
                 from /usr/include/c++/6/bits/char_traits.h:39,
                 from /usr/include/c++/6/ios:40,
                 from /usr/include/c++/6/ostream:38,
                 from /usr/include/c++/6/iostream:39,
                 from /in/foo.cc:1:
/usr/include/c++/6/bits/stl_iterator_base_funcs.h:205:5: note:                 template<class _ForwardIterator> _ForwardIterator std::next(_ForwardIterator, typename std::iterator_traits<_Iter>::difference_type)
     next(_ForwardIterator __x, typename
     ^~~~
/in/foo.cc: In function 'bool ask(ull)':
/in/foo.cc:20:20: error: reference to 'next' is ambiguous
  for(i=head[x];i;i=next[i])
                    ^~~~
/in/foo.cc:7:33: note: candidates are: int next [1000010]
 int a[1010][1010],head[1000010],next[1000010],n,m,q,tot,r,c,i,j,k;
                                 ^~~~
In file included from /usr/include/c++/6/bits/stl_algobase.h:66:0,
                 from /usr/include/c++/6/bits/char_traits.h:39,
                 from /usr/include/c++/6/ios:40,
                 from /usr/include/c++/6/ostream:38,
                 from /usr/include/c++/6/iostream:39,
                 from /in/foo.cc:1:
/usr/include/c++/6/bits/stl_iterator_base_funcs.h:205:5: note:                 template<class _ForwardIterator> _ForwardIterator std::next(_ForwardIterator, typename std::iterator_traits<_Iter>::difference_type)
     next(_ForwardIterator __x, typename
     ^~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:45:12: error: reference to 'hash' is ambiguous
   now=top; hash(now);
            ^~~~
/in/foo.cc:10:6: note: candidates are: void hash(ull)
 void hash(ull now)
      ^~~~
In file included from /usr/include/c++/6/bits/basic_string.h:5643:0,
                 from /usr/include/c++/6/string:52,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/ostream:38,
                 from /usr/include/c++/6/iostream:39,
                 from /in/foo.cc:1:
/usr/include/c++/6/bits/functional_hash.h:58:12: note:                 template<class _Tp> struct std::hash
     struct hash;
            ^~~~
/in/foo.cc:46:58: error: reference to 'hash' is ambiguous
   for(i=r+1;i<=n;i++) now=now*pc-fa[i-r][j]*ppc+fa[i][j],hash(now);
                                                          ^~~~
/in/foo.cc:10:6: note: candidates are: void hash(ull)
 void hash(ull now)
      ^~~~
In file included from /usr/include/c++/6/bits/basic_string.h:5643:0,
                 from /usr/include/c++/6/string:52,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/ostream:38,
                 from /usr/include/c++/6/iostream:39,
                 from /in/foo.cc:1:
/usr/include/c++/6/bits/functional_hash.h:58:12: note:                 template<class _Tp> struct std::hash
     struct hash;
            ^~~~