foo.cpp: In function 'int main()':
foo.cpp:42:5: error: reference to 'next' is ambiguous
     next[etot]=ptr[i],ptr[i]=etot,succ[etot++]=j;
     ^
foo.cpp:16:5: note: candidates are: int next [1000005]
 int next[1000005],ptr[1005],succ[1000005];
     ^
In file included from c:\tdm-gcc-32\lib\gcc\mingw32\4.8.1\include\c++\bits\stl_algobase.h:66:0,
                 from c:\tdm-gcc-32\lib\gcc\mingw32\4.8.1\include\c++\bits\char_traits.h:39,
                 from c:\tdm-gcc-32\lib\gcc\mingw32\4.8.1\include\c++\ios:40,
                 from c:\tdm-gcc-32\lib\gcc\mingw32\4.8.1\include\c++\ostream:38,
                 from c:\tdm-gcc-32\lib\gcc\mingw32\4.8.1\include\c++\iostream:39,
                 from foo.cpp:1:
c:\tdm-gcc-32\lib\gcc\mingw32\4.8.1\include\c++\bits\stl_iterator_base_funcs.h:184:5: note:                 template<class _ForwardIterator> _ForwardIterator std::next(_ForwardIterator, typename std::iterator_traits<_Iter>::difference_type)
     next(_ForwardIterator __x, typename
     ^
foo.cpp:58:29: error: reference to 'next' is ambiguous
   for(i=ptr[stack[top]];i;i=next[i]){
                             ^
foo.cpp:16:5: note: candidates are: int next [1000005]
 int next[1000005],ptr[1005],succ[1000005];
     ^
In file included from c:\tdm-gcc-32\lib\gcc\mingw32\4.8.1\include\c++\bits\stl_algobase.h:66:0,
                 from c:\tdm-gcc-32\lib\gcc\mingw32\4.8.1\include\c++\bits\char_traits.h:39,
                 from c:\tdm-gcc-32\lib\gcc\mingw32\4.8.1\include\c++\ios:40,
                 from c:\tdm-gcc-32\lib\gcc\mingw32\4.8.1\include\c++\ostream:38,
                 from c:\tdm-gcc-32\lib\gcc\mingw32\4.8.1\include\c++\iostream:39,
                 from foo.cpp:1:
c:\tdm-gcc-32\lib\gcc\mingw32\4.8.1\include\c++\bits\stl_iterator_base_funcs.h:184:5: note:                 template<class _ForwardIterator> _ForwardIterator std::next(_ForwardIterator, typename std::iterator_traits<_Iter>::difference_type)
     next(_ForwardIterator __x, typename
     ^