foo.cpp: In function 'void add(int, int, double)':
foo.cpp:14:2: error: reference to 'next' is ambiguous
  next[p]=h[a];
  ^
foo.cpp:6:23: note: candidates are: int next [1000001]
 int h[401],v[1000001],next[1000001],node,p,s,t,x,y,n,q[1000001],value;
                       ^
In file included from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\stl_algobase.h:66:0,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\char_traits.h:39,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\ios:40,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\ostream:38,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\iostream:39,
                 from foo.cpp:1:
c:\mingw\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: In function 'double spfa(int)':
foo.cpp:130:6: error: reference to 'next' is ambiguous
    p=next[p];
      ^
foo.cpp:6:23: note: candidates are: int next [1000001]
 int h[401],v[1000001],next[1000001],node,p,s,t,x,y,n,q[1000001],value;
                       ^
In file included from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\stl_algobase.h:66:0,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\char_traits.h:39,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\ios:40,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\ostream:38,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\iostream:39,
                 from foo.cpp:1:
c:\mingw\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: In function 'int main()':
foo.cpp:147:21: warning: unknown conversion type character 'l' in format [-Wformat=]
  printf("%.2llf",ans);
                     ^
foo.cpp:147:21: warning: too many arguments for format [-Wformat-extra-args]