/in/foo.cc: In function 'int main()':
/in/foo.cc:27:1: error: reference to 'next' is ambiguous
 next[n]=n+1;per(i,n-1,0)if(s[i+1]=='W')next[i]=i+1;else next[i]=next[i+1];
 ^~~~
/in/foo.cc:22:5: note: candidates are: int next [500010]
 int next[maxn];
     ^~~~
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:27:40: error: reference to 'next' is ambiguous
 next[n]=n+1;per(i,n-1,0)if(s[i+1]=='W')next[i]=i+1;else next[i]=next[i+1];
                                        ^~~~
/in/foo.cc:22:5: note: candidates are: int next [500010]
 int next[maxn];
     ^~~~
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:27:57: error: reference to 'next' is ambiguous
 next[n]=n+1;per(i,n-1,0)if(s[i+1]=='W')next[i]=i+1;else next[i]=next[i+1];
                                                         ^~~~
/in/foo.cc:22:5: note: candidates are: int next [500010]
 int next[maxn];
     ^~~~
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:27:65: error: reference to 'next' is ambiguous
 next[n]=n+1;per(i,n-1,0)if(s[i+1]=='W')next[i]=i+1;else next[i]=next[i+1];
                                                                 ^~~~
/in/foo.cc:22:5: note: candidates are: int next [500010]
 int next[maxn];
     ^~~~
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:28:30: error: reference to 'next' is ambiguous
 for(int i=0;i<=n;i+=2)lp.ins(next[i]+next[i]-i,i);
                              ^~~~
/in/foo.cc:22:5: note: candidates are: int next [500010]
 int next[maxn];
     ^~~~
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:28:38: error: reference to 'next' is ambiguous
 for(int i=0;i<=n;i+=2)lp.ins(next[i]+next[i]-i,i);
                                      ^~~~
/in/foo.cc:22:5: note: candidates are: int next [500010]
 int next[maxn];
     ^~~~
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
     ^~~~