/in/foo.cc: In function 'void Init()':
/in/foo.cc:45:8: warning: unused variable 'j' [-Wunused-variable]
  int i,j;
        ^
/in/foo.cc: In function 'void rowmore(int, int)':
/in/foo.cc:107:4: error: reference to 'next' is ambiguous
    next=row[l];
    ^~~~
/in/foo.cc:12:29: note: candidates are: node next
 }row[N],column[N],now,start,next;
                             ^~~~
In file included from /usr/include/c++/7/bits/stl_algobase.h:66:0,
                 from /usr/include/c++/7/algorithm:61,
                 from /in/foo.cc:3:
/usr/include/c++/7/bits/stl_iterator_base_funcs.h:208:5: note:                 template<class _ForwardIterator> _ForwardIterator std::next(_ForwardIterator, typename std::iterator_traits<_Iter>::difference_type)
     next(_ForwardIterator __x, typename
     ^~~~
/in/foo.cc:110:4: error: reference to 'next' is ambiguous
    next.x=now.x;
    ^~~~
/in/foo.cc:12:29: note: candidates are: node next
 }row[N],column[N],now,start,next;
                             ^~~~
In file included from /usr/include/c++/7/bits/stl_algobase.h:66:0,
                 from /usr/include/c++/7/algorithm:61,
                 from /in/foo.cc:3:
/usr/include/c++/7/bits/stl_iterator_base_funcs.h:208:5: note:                 template<class _ForwardIterator> _ForwardIterator std::next(_ForwardIterator, typename std::iterator_traits<_Iter>::difference_type)
     next(_ForwardIterator __x, typename
     ^~~~
/in/foo.cc:111:4: error: reference to 'next' is ambiguous
    next.y=rowmax[next.x];
    ^~~~
/in/foo.cc:12:29: note: candidates are: node next
 }row[N],column[N],now,start,next;
                             ^~~~
In file included from /usr/include/c++/7/bits/stl_algobase.h:66:0,
                 from /usr/include/c++/7/algorithm:61,
                 from /in/foo.cc:3:
/usr/include/c++/7/bits/stl_iterator_base_funcs.h:208:5: note:                 template<class _ForwardIterator> _ForwardIterator std::next(_ForwardIterator, typename std::iterator_traits<_Iter>::difference_type)
     next(_ForwardIterator __x, typename
     ^~~~
/in/foo.cc:111:18: error: reference to 'next' is ambiguous
    next.y=rowmax[next.x];
                  ^~~~
/in/foo.cc:12:29: note: candidates are: node next
 }row[N],column[N],now,start,next;
                             ^~~~
In file included from /usr/include/c++/7/bits/stl_algobase.h:66:0,
                 from /usr/include/c++/7/algorithm:61,
                 from /in/foo.cc:3:
/usr/include/c++/7/bits/stl_iterator_base_funcs.h:208:5: 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 rowless(int, int)':
/in/foo.cc:126:4: error: reference to 'next' is ambiguous
    next=row[l];
    ^~~~
/in/foo.cc:12:29: note: candidates are: node next
 }row[N],column[N],now,start,next;
                             ^~~~
In file included from /usr/include/c++/7/bits/stl_algobase.h:66:0,
                 from /usr/include/c++/7/algorithm:61,
                 from /in/foo.cc:3:
/usr/include/c++/7/bits/stl_iterator_base_funcs.h:208:5: note:                 template<class _ForwardIterator> _ForwardIterator std::next(_ForwardIterator, typename std::iterator_traits<_Iter>::difference_type)
     next(_ForwardIterator __x, typename
     ^~~~
/in/foo.cc:129:4: error: reference to 'next' is ambiguous
    next.x=now.x;
    ^~~~
/in/foo.cc:12:29: note: candidates are: node next
 }row[N],column[N],now,start,next;
                             ^~~~
In file included from /usr/include/c++/7/bits/stl_algobase.h:66:0,
                 from /usr/include/c++/7/algorithm:61,
                 from /in/foo.cc:3:
/usr/include/c++/7/bits/stl_iterator_base_funcs.h:208:5: note:                 template<class _ForwardIterator> _ForwardIterator std::next(_ForwardIterator, typename std::iterator_traits<_Iter>::difference_type)
     next(_ForwardIterator __x, typename
     ^~~~
/in/foo.cc:130:4: error: reference to 'next' is ambiguous
    next.y=rowmin[next.x];
    ^~~~
/in/foo.cc:12:29: note: candidates are: node next
 }row[N],column[N],now,start,next;
                             ^~~~
In file included from /usr/include/c++/7/bits/stl_algobase.h:66:0,
                 from /usr/include/c++/7/algorithm:61,
                 from /in/foo.cc:3:
/usr/include/c++/7/bits/stl_iterator_base_funcs.h:208:5: note:                 template<class _ForwardIterator> _ForwardIterator std::next(_ForwardIterator, typename std::iterator_traits<_Iter>::difference_type)
     next(_ForwardIterator __x, typename
     ^~~~
/in/foo.cc:130:18: error: reference to 'next' is ambiguous
    next.y=rowmin[next.x];
                  ^~~~
/in/foo.cc:12:29: note: candidates are: node next
 }row[N],column[N],now,start,next;
                             ^~~~
In file included from /usr/include/c++/7/bits/stl_algobase.h:66:0,
                 from /usr/include/c++/7/algorithm:61,
                 from /in/foo.cc:3:
/usr/include/c++/7/bits/stl_iterator_base_funcs.h:208:5: 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 columnmore(int, int)':
/in/foo.cc:145:4: error: reference to 'next' is ambiguous
    next=column[l];
    ^~~~
/in/foo.cc:12:29: note: candidates are: node next
 }row[N],column[N],now,start,next;
                             ^~~~
In file included from /usr/include/c++/7/bits/stl_algobase.h:66:0,
                 from /usr/include/c++/7/algorithm:61,
                 from /in/foo.cc:3:
/usr/include/c++/7/bits/stl_iterator_base_funcs.h:208:5: note:                 template<class _ForwardIterator> _ForwardIterator std::next(_ForwardIterator, typename std::iterator_traits<_Iter>::difference_type)
     next(_ForwardIterator __x, typename
     ^~~~
/in/foo.cc:148:4: error: reference to 'next' is ambiguous
    next.y=now.y;
    ^~~~
/in/foo.cc:12:29: note: candidates are: node next
 }row[N],column[N],now,start,next;
                             ^~~~
In file included from /usr/include/c++/7/bits/stl_algobase.h:66:0,
                 from /usr/include/c++/7/algorithm:61,
                 from /in/foo.cc:3:
/usr/include/c++/7/bits/stl_iterator_base_funcs.h:208:5: note:                 template<class _ForwardIterator> _ForwardIterator std::next(_ForwardIterator, typename std::iterator_traits<_Iter>::difference_type)
     next(_ForwardIterator __x, typename
     ^~~~
/in/foo.cc:149:4: error: reference to 'next' is ambiguous
    next.x=columnmax[next.y+N];
    ^~~~
/in/foo.cc:12:29: note: candidates are: node next
 }row[N],column[N],now,start,next;
                             ^~~~
In file included from /usr/include/c++/7/bits/stl_algobase.h:66:0,
                 from /usr/include/c++/7/algorithm:61,
                 from /in/foo.cc:3:
/usr/include/c++/7/bits/stl_iterator_base_funcs.h:208:5: note:                 template<class _ForwardIterator> _ForwardIterator std::next(_ForwardIterator, typename std::iterator_traits<_Iter>::difference_type)
     next(_ForwardIterator __x, typename
     ^~~~
/in/foo.cc:149:21: error: reference to 'next' is ambiguous
    next.x=columnmax[next.y+N];
                     ^~~~
/in/foo.cc:12:29: note: candidates are: node next
 }row[N],column[N],now,start,next;
                             ^~~~
In file included from /usr/include/c++/7/bits/stl_algobase.h:66:0,
                 from /usr/include/c++/7/algorithm:61,
                 from /in/foo.cc:3:
/usr/include/c++/7/bits/stl_iterator_base_funcs.h:208:5: 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 columnless(int, int)':
/in/foo.cc:164:4: error: reference to 'next' is ambiguous
    next=column[l];
    ^~~~
/in/foo.cc:12:29: note: candidates are: node next
 }row[N],column[N],now,start,next;
                             ^~~~
In file include