foo.cpp: In function 'void Build_Tree(int, int, int)':
foo.cpp:32:42: error: reference to 'rank' is ambiguous
     if ( x == y ) tr[ i ].mintr = E_val[ rank[ x ] ] ;
                                          ^
foo.cpp:15:66: note: candidates are: int rank [300010]
 int head[maxN] , father[maxN], DFN[maxN], hv[maxN],/*ind[maxN],*/rank[maxN], E_val[maxN], start[maxN], pre[maxN];
                                                                  ^
In file included from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\move.h:57:0,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\stl_pair.h:59,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\stl_algobase.h:64,
                 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++\istream:38,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\sstream:38,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\complex:45,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\ccomplex:38,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\mingw32\bits\stdc++.h:52,
                 from foo.cpp:1:
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\type_traits:1243:12: note:                 template<class> struct std::rank
     struct rank
            ^
foo.cpp: In function 'void DFS(int, int)':
foo.cpp:87:5: error: reference to 'rank' is ambiguous
     rank[ dfs_num ] = x ;
     ^
foo.cpp:15:66: note: candidates are: int rank [300010]
 int head[maxN] , father[maxN], DFN[maxN], hv[maxN],/*ind[maxN],*/rank[maxN], E_val[maxN], start[maxN], pre[maxN];
                                                                  ^
In file included from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\move.h:57:0,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\stl_pair.h:59,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\stl_algobase.h:64,
                 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++\istream:38,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\sstream:38,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\complex:45,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\ccomplex:38,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\mingw32\bits\stdc++.h:52,
                 from foo.cpp:1:
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\type_traits:1243:12: note:                 template<class> struct std::rank
     struct rank
            ^
foo.cpp: In function 'void DEBUG__(int)':
foo.cpp:135:71: error: reference to 'rank' is ambiguous
     for ( int i = 1 ; i <= n ; ++i )printf ("%d : %d %d\n", i , E_val[rank[ i ] ] , E_val[ i ]) ;
                                                                       ^
foo.cpp:15:66: note: candidates are: int rank [300010]
 int head[maxN] , father[maxN], DFN[maxN], hv[maxN],/*ind[maxN],*/rank[maxN], E_val[maxN], start[maxN], pre[maxN];
                                                                  ^
In file included from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\move.h:57:0,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\stl_pair.h:59,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\stl_algobase.h:64,
                 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++\istream:38,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\sstream:38,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\complex:45,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c+