View Compilation Error

0_0_32477212_6106.cpp: In function 'int get_hash(std::string)':
0_0_32477212_6106.cpp:38:18: error: reference to 'hash' is ambiguous
         s += k * hash[i];
                  ^
0_0_32477212_6106.cpp:10:5: note: candidates are: int hash [9]
 int hash[9] = {1, 1, 2, 6, 24, 120, 720, 5040, 40320};
     ^
In file included from GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/basic_string.h:3068:0,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/string:52,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/locale_classes.h:40,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/ios_base.h:41,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/ios:42,
                 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_32477212_6106.cpp:1:
GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/functional_hash.h:58:12: note:                 template<class _Tp> struct std::hash
     struct hash;
            ^