/in/foo.cc: In function 'void add(int, int, int)':
/in/foo.cc:19:17: error: reference to 'next' is ambiguous
     go[++tot]=y;next[tot]=head[x][z];head[x][z]=tot;
                 ^~~~
/in/foo.cc:12:17: note: candidates are: int next [200005]
 int head[N][27],next[N],go[N],a[N],head1[N][27];
                 ^~~~
In file included from /usr/include/c++/6/bits/stl_algobase.h:66:0,
                 from /usr/include/c++/6/algorithm:61,
                 from /in/foo.cc:2:
/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:20:17: error: reference to 'next' is ambiguous
     go[++tot]=x;next[tot]=head1[y][z];head1[y][z]=tot;
                 ^~~~
/in/foo.cc:12:17: note: candidates are: int next [200005]
 int head[N][27],next[N],go[N],a[N],head1[N][27];
                 ^~~~
In file included from /usr/include/c++/6/bits/stl_algobase.h:66:0,
                 from /usr/include/c++/6/algorithm:61,
                 from /in/foo.cc:2:
/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 'void bfs()':
/in/foo.cc:39:38: error: reference to 'next' is ambiguous
             for(int j=head[y][i];j;j=next[j])
                                      ^~~~
/in/foo.cc:12:17: note: candidates are: int next [200005]
 int head[N][27],next[N],go[N],a[N],head1[N][27];
                 ^~~~
In file included from /usr/include/c++/6/bits/stl_algobase.h:66:0,
                 from /usr/include/c++/6/algorithm:61,
                 from /in/foo.cc:2:
/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:51:39: error: reference to 'next' is ambiguous
             for(int i=head1[x][z];i;i=next[i])
                                       ^~~~
/in/foo.cc:12:17: note: candidates are: int next [200005]
 int head[N][27],next[N],go[N],a[N],head1[N][27];
                 ^~~~
In file included from /usr/include/c++/6/bits/stl_algobase.h:66:0,
                 from /usr/include/c++/6/algorithm:61,
                 from /in/foo.cc:2:
/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:70:32: warning: format '%s' expects argument of type 'char*', but argument 4 has type 'char (*)[2]' [-Wformat=]
         scanf("%d%d%s",&x,&y,&s);
                                ^