Language: C++

#include<iostream>
#include<unordered_set>
#include<array>

using namespace std;

typedef array<array<signed char,3>,3> Die;

int main(){
  for(int x,y;cin>>x>>y,x;){
    char g[3][3];
    for(int i=0;i<3;i++){
      for(int j=0;j<3;j++){
	cin>>g[i][j];
      }
    }
    unordered_set<Die> s[32],u;
    Die d{};
    d[y-1][x-1]=-1;
    s[0].insert(d);
    u.insert(d);
    for(int i=0;i<=30;i++){
      for(auto e:s[i]){
	bool f=false;
	int ey,ex;
	int c=0;
	for(int j=0;j<3;j++){
	  for(int k=0;k<3;k++){
	    if(e[j][k]==-1){
	      f|=g[j][k]!='E';
	      ey=j;
	      ex=k;
	    }else{
	      f|=g[j][k]!="WBRWBR"[e[j][k]];
	    }
	    c+=g[j][k]!='E'&&(e[j][k]==-1||g[j][k]!="WBRWBR"[e[j][k]]);
	  }
	}
	if(!f){
	  cout<<i<<endl;
	  goto next;
	}
	if(c+i>30)continue;
	if(i<30){
	  static int dy[]={-1,0,1,0};
	  static int dx[]={0,1,0,-1};
	  for(int j=0;j<4;j++){
	    int ny=ey+dy[j];
	    int nx=ex+dx[j];
	    if(0<=ny&&ny<3&&0<=nx&&nx<3){
	      auto n=e;
	      n[ny][nx]=-1;
	      n[ey][ex]=(e[ny][nx]+((e[ny][nx]%2^j%2)?1:5))%6;
	      //	      if(u.insert(n).second){
		s[i+1].insert(n);
		//	      }
	    }
	  }
	}
      }
      s[i].clear();
    }
    cout<<-1<<endl;
  next:
    ;
  }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:17:28: error: use of deleted function 'std::unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set() [with _Value = std::array<std::array<signed char, 3>, 3>; _Hash = std::hash<std::array<std::array<signed char, 3>, 3> >; _Pred = std::equal_to<std::array<std::array<signed char, 3>, 3> >; _Alloc = std::allocator<std::array<std::array<signed char, 3>, 3> >]'
   17 |     unordered_set<Die> s[32],u;
      |                            ^
In file included from /usr/include/c++/14/unordered_set:41,
                 from a.cc:2:
/usr/include/c++/14/bits/unordered_set.h:142:7: note: 'std::unordered_set<_Value, _Hash, _Pred, _Alloc>::unordered_set() [with _Value = std::array<std::array<signed char, 3>, 3>; _Hash = std::hash<std::array<std::array<signed char, 3>, 3> >; _Pred = std::equal_to<std::array<std::array<signed char, 3>, 3> >; _Alloc = std::allocator<std::array<std::array<signed char, 3>, 3> >]' is implicitly deleted because the default definition would be ill-formed:
  142 |       unordered_set() = default;
      |       ^~~~~~~~~~~~~
/usr/include/c++/14/bits/unordered_set.h: At global scope:
/usr/include/c++/14/bits/unordered_set.h:142:7: error: use of deleted function 'std::_Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal, _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::_Hashtable() [with _Key = std::array<std::array<signed char, 3>, 3>; _Value = std::array<std::array<signed char, 3>, 3>; _Alloc = std::allocator<std::array<std::array<signed char, 3>, 3> >; _ExtractKey = std::__detail::_Identity; _Equal = std::equal_to<std::array<std::array<signed char, 3>, 3> >; _Hash = std::hash<std::array<std::array<signed char, 3>, 3> >; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; _RehashPolicy = std::__detail::_Prime_rehash_policy; _Traits = std::__detail::_Hashtable_traits<true, true, true>]'
In file included from /usr/include/c++/14/bits/unordered_set.h:33:
/usr/include/c++/14/bits/hashtable.h:539:7: note: 'std::_Hashtable<_Key, _Value, _Alloc, _ExtractKey, _Equal, _Hash, _RangeHash, _Unused, _RehashPolicy, _Traits>::_Hashtable() [with _Key = std::array<std::array<signed char, 3>, 3>; _Value = std::array<std::array<signed char, 3>, 3>; _Alloc = std::allocator<std::array<std::array<signed char, 3>, 3> >; _ExtractKey = std::__detail::_Identity; _Equal = std::equal_to<std::array<std::array<signed char, 3>, 3> >; _Hash = std::hash<std::array<std::array<signed char, 3>, 3> >; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; _RehashPolicy = std::__detail::_Prime_rehash_policy; _Traits = std::__detail::_Hashtable_traits<true, true, true>]' is implicitly deleted because the default definition would be ill-formed:
  539 |       _Hashtable() = default;
      |       ^~~~~~~~~~
/usr/include/c++/14/bits/hashtable.h:539:7: error: use of deleted function 'std::__detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal, _Hash, _RangeHash, _Unused, _Traits>::_Hashtable_base() [with _Key = std::array<std::array<signed char, 3>, 3>; _Value = std::array<std::array<signed char, 3>, 3>; _ExtractKey = std::__detail::_Identity; _Equal = std::equal_to<std::array<std::array<signed char, 3>, 3> >; _Hash = std::hash<std::array<std::array<signed char, 3>, 3> >; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; _Traits = std::__detail::_Hashtable_traits<true, true, true>]'
In file included from /usr/include/c++/14/bits/hashtable.h:35:
/usr/include/c++/14/bits/hashtable_policy.h:1731:7: note: 'std::__detail::_Hashtable_base<_Key, _Value, _ExtractKey, _Equal, _Hash, _RangeHash, _Unused, _Traits>::_Hashtable_base() [with _Key = std::array<std::array<signed char, 3>, 3>; _Value = std::array<std::array<signed char, 3>, 3>; _ExtractKey = std::__detail::_Identity; _Equal = std::equal_to<std::array<std::array<signed char, 3>, 3> >; _Hash = std::hash<std::array<std::array<signed char, 3>, 3> >; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; _Traits = std::__detail::_Hashtable_traits<true, true, true>]' is implicitly deleted because the default definition would be ill-formed:
 1731 |       _Hashtable_base() = default;
      |       ^~~~~~~~~~~~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1731:7: error: use of deleted function 'std::__detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Hash, _RangeHash, _Unused, __cache_hash_code>::_Hash_code_base() [with _Key = std::array<std::array<signed char, 3>, 3>; _Value = std::array<std::array<signed char, 3>, 3>; _ExtractKey = std::__detail::_Identity; _Hash = std::hash<std::array<std::array<signed char, 3>, 3> >; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; bool __cache_hash_code = true]'
/usr/include/c++/14/bits/hashtable_policy.h: In instantiation of 'std::__detail::_Hashtable_ebo_helper<_Nm, _Tp, true>::_Hashtable_ebo_helper() [with int _Nm = 1; _Tp = std::hash<std::array<std::array<signed char, 3>, 3> >]':
/usr/include/c++/14/bits/hashtable_policy.h:1328:7:   required from here
 1328 |       _Hash_code_base() = default;
      |       ^~~~~~~~~~~~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1245:49: error: use of deleted function 'std::hash<std::array<std::array<signed char, 3>, 3> >::hash()'
 1245 |       _Hashtable_ebo_helper() noexcept(noexcept(_Tp())) : _Tp() { }
      |                                                 ^~~~~
In file included from /usr/include/c++/14/string_view:50,
                 from /usr/include/c++/14/bits/basic_string.h:47,
                 from /usr/include/c++/14/string:54,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:1:
/usr/include/c++/14/bits/functional_hash.h:102:12: note: 'std::hash<std::array<std::array<signed char, 3>, 3> >::hash()' is implicitly deleted because the default definition would be ill-formed:
  102 |     struct hash : __hash_enum<_Tp>
      |            ^~~~
/usr/include/c++/14/bits/functional_hash.h:102:12: error: no matching function for call to 'std::__hash_enum<std::array<std::array<signed char, 3>, 3>, false>::__hash_enum()'
/usr/include/c++/14/bits/functional_hash.h:83:7: note: candidate: 'std::__hash_enum<_Tp, <anonymous> >::__hash_enum(std::__hash_enum<_Tp, <anonymous> >&&) [with _Tp = std::array<std::array<signed char, 3>, 3>; bool <anonymous> = false]'
   83 |       __hash_enum(__hash_enum&&);
      |       ^~~~~~~~~~~
/usr/include/c++/14/bits/functional_hash.h:83:7: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/functional_hash.h:102:12: error: 'std::__hash_enum<_Tp, <anonymous> >::~__hash_enum() [with _Tp = std::array<std::array<signed char, 3>, 3>; bool <anonymous> = false]' is private within this context
  102 |     struct hash : __hash_enum<_Tp>
      |            ^~~~
/usr/include/c++/14/bits/functional_hash.h:84:7: note: declared private here
   84 |       ~__hash_enum();
      |       ^
/usr/include/c++/14/bits/hashtable_policy.h:1245:49: note: use '-fdiagnostics-all-candidates' to display considered candidates
 1245 |       _Hashtable_ebo_helper() noexcept(noexcept(_Tp())) : _Tp() { }
      |                                                 ^~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1328:7: note: 'std::__detail::_Hash_code_base<_Key, _Value, _ExtractKey, _Hash, _RangeHash, _Unused, __cache_hash_code>::_Hash_code_base() [with _Key = std::array<std::array<signed char, 3>, 3>; _Value = std::array<std::array<signed char, 3>, 3>; _ExtractKey = std::__detail::_Identity; _Hash = std::hash<std::array<std::array<signed char, 3>, 3> >; _RangeHash = std::__detail::_Mod_range_hashing; _Unused = std::__detail::_Default_ranged_hash; bool __cache_hash_code = true]' is implicitly deleted because the default definition would be ill-formed:
 1328 |       _Hash_code_base() = default;
      |       ^~~~~~~~~~~~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1328:7: error: use of deleted function 'std::__detail::_Hashtable_ebo_helper<1, std::hash<std::array<std::array<signed char, 3>, 3> >, true>::~_Hashtable_ebo_helper()'
/usr/include/c++/14/bits/hashtable_policy.h:1242:12: note: 'std::__detail::_Hashtable_ebo_helper<1, std::hash<std::array<std::array<signed char, 3>, 3> >, true>::~_Hashtable_ebo_helper()' is implicitly deleted because the default definition would be ill-formed:
 1242 |     struct _Hashtable_ebo_helper<_Nm, _Tp, true>
      |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1242:12: error: use of deleted function 'std::hash<std::array<std::array<signed char, 3>, 3> >::~hash()'
/usr/include/c++/14/bits/functional_hash.h:102:12: note: 'std::hash<std::array<std::array<signed char, 3>, 3> >::~hash()' is implicitly deleted because the default definition would be ill-formed:
  102 |     struct hash : __hash_enum<_Tp>
      |            ^~~~
/usr/include/c++/14/bits/functional_hash.h:102:12: error: 'std::__hash_enum<_Tp, <anonymous> >::~__hash_enum() [with _Tp = std::array<std::array<signed char, 3>, 3>; bool <anonymous> = false]' is private within this context
/usr/include/c++/14/bits/functional_hash.h:84:7: note: declared private here
   84 |       ~__hash_enum();
      |       ^
/usr/include/c++/14/bits/hashtable_policy.h:1731:7: note: use '-fdiagnostics-all-candidates' to display considered candidates
 1731 |       _Hashtable_base() = default;
      |       ^~~~~~~~~~~~~~~
/usr/include/c++/14/bits/hashtable_policy.h:1731:7: error: use of deleted function 'std::__detail::_Hash_code_base<std::array<std::array<signed char, 3>, 3>, std::array<std::array<signed char, 3>, 3>, std::__detail::_Identity, std::hash<std::array<std::array<signed char, 3>, 3> >, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, true>::~_Hash_code_base()'
/usr/include/c++/14/bits/hashtable_policy.h:1306:12: note: 'std::__detail::_Hash_code_base<std::array<std::array<