answer.code:38:24: error: field ‘arr’ has incomplete type ‘std::array<int, 30>’
   38 |     std::array<int, N> arr{};
      |                        ^~~
In file included from /usr/include/c++/13/bits/uses_allocator_args.h:38,
                 from /usr/include/c++/13/bits/memory_resource.h:41,
                 from /usr/include/c++/13/string:58,
                 from /usr/include/c++/13/bits/locale_classes.h:40,
                 from /usr/include/c++/13/bits/ios_base.h:41,
                 from /usr/include/c++/13/iomanip:42,
                 from answer.code:1:
/usr/include/c++/13/tuple:2005:45: note: declaration of ‘struct std::array<int, 30>’
 2005 |   template<typename _Tp, size_t _Nm> struct array;
      |                                             ^~~~~
answer.code: In function ‘std::vector<perm_t> simplify_basis(const std::vector<perm_t>&, int)’:
answer.code:60:10: error: ‘optional’ is not a member of ‘std’
   60 |     std::optional<perm_t> added[N][N];
      |          ^~~~~~~~
answer.code:12:1: note: ‘std::optional’ is defined in header ‘<optional>’; did you forget to ‘#include <optional>’?
   11 | #include "queue"
  +++ |+#include <optional>
   12 | //#include <bits/stdc++.h>
answer.code:60:25: error: expected primary-expression before ‘>’ token
   60 |     std::optional<perm_t> added[N][N];
      |                         ^
answer.code:60:27: error: ‘added’ was not declared in this scope
   60 |     std::optional<perm_t> added[N][N];
      |                           ^~~~~
answer.code: In function ‘int calc_perms(const std::vector<perm_t>&, int)’:
answer.code:89:12: error: ‘optional’ was not declared in this scope
   89 |     vector<optional<perm_t>> r(n);
      |            ^~~~~~~~
answer.code:89:12: note: ‘std::optional’ is defined in header ‘<optional>’; did you forget to ‘#include <optional>’?
answer.code:89:27: error: template argument 1 is invalid
   89 |     vector<optional<perm_t>> r(n);
      |                           ^~
answer.code:89:27: error: template argument 2 is invalid
answer.code:90:6: error: invalid types ‘int[int]’ for array subscript
   90 |     r[n - 1] = perm_t{};
      |      ^
answer.code:99:19: error: invalid types ‘int[int]’ for array subscript
   99 |             if (!r[u].has_value()) {
      |                   ^
answer.code:100:18: error: invalid types ‘int[int]’ for array subscript
  100 |                 r[u] = e * r[v].value();
      |                  ^
answer.code:100:29: error: invalid types ‘int[int]’ for array subscript
  100 |                 r[u] = e * r[v].value();
      |                             ^
answer.code:110:33: error: invalid types ‘int[int]’ for array subscript
  110 |             new_base.push_back(r[u].value().inv() * o * e);
      |                                 ^
answer.code:113:29: error: invalid types ‘int[int]’ for array subscript
  113 |         new_base.push_back(r[u].value().inv() * e);
      |                             ^