/in/foo.cc: In function 'void update(int, int, int, int, int, int)':
/in/foo.cc:44:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   int mid=l+r>>1;
           ~^~
/in/foo.cc: In function 'll query(int, int, int, int)':
/in/foo.cc:58:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   int mid=l+r>>1;
           ~^~
/in/foo.cc: In function 'void add(int, int)':
/in/foo.cc:66:2: error: reference to 'next' is ambiguous
  next[ce]=c[x].head;
  ^~~~
/in/foo.cc:13:5: note: candidates are: int next [310000]
 int next[N],to[N],ce;
     ^~~~
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:3:
/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 slove(int, int, int, int)':
/in/foo.cc:78:11: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int mid=l+r>>1;
          ~^~
/in/foo.cc:101:30: error: reference to 'next' is ambiguous
   for(j=c[i].head,temp=0;j;j=next[j])
                              ^~~~
/in/foo.cc:13:5: note: candidates are: int next [310000]
 int next[N],to[N],ce;
     ^~~~
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:3:
/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:122:10: warning: unused variable 'j' [-Wunused-variable]
  int q,i,j,k,x,y;
          ^
/in/foo.cc:122:12: warning: unused variable 'k' [-Wunused-variable]
  int q,i,j,k,x,y;
            ^
/in/foo.cc:122:16: warning: unused variable 'y' [-Wunused-variable]
  int q,i,j,k,x,y;
                ^