/in/foo.cc:9:24: error: reference to 'hash' is ambiguous
 int f[MAXN*2+100], map[hash+100];
                        ^~~~
/in/foo.cc:6:11: note: candidates are: const int hash
 const int hash = 6000,MAXN = 10000;
           ^~~~
In file included from /usr/include/c++/6/bits/basic_string.h:5643:0,
                 from /usr/include/c++/6/string:52,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/ostream:38,
                 from /usr/include/c++/6/iostream:39,
                 from /in/foo.cc:1:
/usr/include/c++/6/bits/functional_hash.h:58:12: note:                 template<class _Tp> struct std::hash
     struct hash;
            ^~~~
/in/foo.cc: In function 'int Hash(int)':
/in/foo.cc:13:13: error: reference to 'hash' is ambiguous
 int bri = x%hash;
             ^~~~
/in/foo.cc:6:11: note: candidates are: const int hash
 const int hash = 6000,MAXN = 10000;
           ^~~~
In file included from /usr/include/c++/6/bits/basic_string.h:5643:0,
                 from /usr/include/c++/6/string:52,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/ostream:38,
                 from /usr/include/c++/6/iostream:39,
                 from /in/foo.cc:1:
/usr/include/c++/6/bits/functional_hash.h:58:12: note:                 template<class _Tp> struct std::hash
     struct hash;
            ^~~~
/in/foo.cc:14:7: error: 'map' was not declared in this scope
 while(map[bri] != -1 && map[bri] != x)
       ^~~
/in/foo.cc:15:15: error: reference to 'hash' is ambiguous
 bri = (bri+1)%hash;
               ^~~~
/in/foo.cc:6:11: note: candidates are: const int hash
 const int hash = 6000,MAXN = 10000;
           ^~~~
In file included from /usr/include/c++/6/bits/basic_string.h:5643:0,
                 from /usr/include/c++/6/string:52,
                 from /usr/include/c++/6/bits/locale_classes.h:40,
                 from /usr/include/c++/6/bits/ios_base.h:41,
                 from /usr/include/c++/6/ios:42,
                 from /usr/include/c++/6/ostream:38,
                 from /usr/include/c++/6/iostream:39,
                 from /in/foo.cc:1:
/usr/include/c++/6/bits/functional_hash.h:58:12: note:                 template<class _Tp> struct std::hash
     struct hash;
            ^~~~
/in/foo.cc:16:1: error: 'map' was not declared in this scope
 map[bri] = x;
 ^~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:36:8: error: 'map' was not declared in this scope
 memset(map, -1, sizeof(map));
        ^~~