View Compilation Error

0_0_32866568_16216.cpp: In function 'void dfs2(int, int)':
0_0_32866568_16216.cpp:40:5: error: reference to 'rank' is ambiguous
     rank[tid[u]]=u;
     ^
0_0_32866568_16216.cpp:12:52: note: candidates are: int rank [201000]
 int siz[NN],son[NN],top[NN],fa[NN],dep[NN],tid[NN],rank[NN];
                                                    ^
In file included from GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/move.h:57:0,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/stl_pair.h:59,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/stl_algobase.h:64,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/char_traits.h:39,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/ios:40,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/ostream:38,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/iostream:39,
                 from 0_0_32866568_16216.cpp:1:
GCC4.9.2/x86_64-w64-mingw32/include/c++/type_traits:1340:12: note:                 template<class> struct std::rank
     struct rank
            ^