foo.cpp: In function 'void bfs()':
foo.cpp:49:21: error: reference to 'hash' is ambiguous
                 if (hash[k]==2)
                     ^
foo.cpp:14:5: note: candidates are: int hash [362890]
 int hash[362890];
     ^
In file included from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\basic_string.h:3033:0,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\string:52,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\locale_classes.h:40,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\ios_base.h:41,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\ios:42,
                 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:4:
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\functional_hash.h:58:12: note:                 template<class _Tp> struct std::hash
     struct hash;
            ^
foo.cpp:54:21: error: reference to 'hash' is ambiguous
                 if (hash[k]==1) tail--;
                     ^
foo.cpp:14:5: note: candidates are: int hash [362890]
 int hash[362890];
     ^
In file included from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\basic_string.h:3033:0,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\string:52,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\locale_classes.h:40,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\ios_base.h:41,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\ios:42,
                 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:4:
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\functional_hash.h:58:12: note:                 template<class _Tp> struct std::hash
     struct hash;
            ^
foo.cpp:55:17: error: reference to 'hash' is ambiguous
                 hash[k]=1;
                 ^
foo.cpp:14:5: note: candidates are: int hash [362890]
 int hash[362890];
     ^
In file included from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\basic_string.h:3033:0,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\string:52,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\locale_classes.h:40,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\ios_base.h:41,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\ios:42,
                 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:4:
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\functional_hash.h:58:12: note:                 template<class _Tp> struct std::hash
     struct hash;
            ^
foo.cpp:65:21: error: reference to 'hash' is ambiguous
                 if (hash[k]==2)
                     ^
foo.cpp:14:5: note: candidates are: int hash [362890]
 int hash[362890];
     ^
In file included from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\basic_string.h:3033:0,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\string:52,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\locale_classes.h:40,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\ios_base.h:41,
                 from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\ios:42,
                 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:4:
c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\bits\functional_hash.h:58:12: note:                 template<class _Tp> struct std::hash
     struct hash;
            ^
foo.cpp:70:21: error: reference to 'hash' is ambiguous
                 if (hash[k]==1) tail--;
                     ^
foo.cpp:14:5: note: candida