answer.code: In function ‘std::ostream& std::print_tuple_utils(ostream&, const T&)’:
answer.code:29:90: warning: ‘if constexpr’ only available with ‘-std=c++17’ or ‘-std=gnu++17’ [-Wc++17-extensions]
   29 | template <size_t i, class T> ostream &print_tuple_utils(ostream &out, const T &tup) { if constexpr(i == tuple_size<T>::value) return out << ")"; else return print_tuple_utils<i + 1, T>(out << (i ? ", " : "(") << get<i>(tup), tup); }
      |                                                                                          ^~~~~~~~~
answer.code: In function ‘void process()’:
answer.code:225:30: error: missing template arguments before ‘{’ token
  225 |         tie(odd, even) = pair{(even - C(2, x) * mul[k - 2]) * 2 + C(k + k, x) - odd, odd - even};
      |                              ^
answer.code: In function ‘int main()’:
answer.code:16:62: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   16 | #define     file(name)  if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
      |                                                       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
answer.code:232:5: note: in expansion of macro ‘file’
  232 |     file("test");
      |     ^~~~
answer.code:16:95: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   16 | #define     file(name)  if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
      |                                                                                        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
answer.code:232:5: note: in expansion of macro ‘file’
  232 |     file("test");
      |     ^~~~