answer.code: In function ‘void solve()’:
answer.code:89:5: error: ‘bitset’ was not declared in this scope
   89 |     bitset<1000> a[C], b[K];
      |     ^~~~~~
answer.code:24:1: note: ‘std::bitset’ is defined in header ‘<bitset>’; did you forget to ‘#include <bitset>’?
   23 | #include <climits>
  +++ |+#include <bitset>
   24 | 
answer.code:89:18: error: ‘a’ was not declared in this scope
   89 |     bitset<1000> a[C], b[K];
      |                  ^
answer.code:89:24: error: ‘b’ was not declared in this scope
   89 |     bitset<1000> a[C], b[K];
      |                        ^
answer.code:122:26: error: ‘res’ was not declared in this scope
  122 |             bitset<1000> res = (b[j] & (b[j] ^ a[i]));
      |                          ^~~