answer.code:2:1: error: ‘vector’ does not name a type
    2 | vector<int> B;
      | ^~~~~~
answer.code:3:1: error: ‘vector’ does not name a type
    3 | vector<int> Q;
      | ^~~~~~
answer.code: In function ‘int count_ways(int, int)’:
answer.code:7:20: error: ‘B’ was not declared in this scope
    7 |                 if(B[i] == 1) B[i] = 0;
      |                    ^
answer.code:11:21: error: ‘B’ was not declared in this scope
   11 |         for(auto a: B){
      |                     ^
answer.code: In function ‘void init(int, int, std::vector<int>, std::vector<int>)’:
answer.code:19:17: error: ‘B’ was not declared in this scope
   19 |                 B.push_back(num);
      |                 ^
answer.code:22:17: error: ‘Q’ was not declared in this scope
   22 |                 Q.push_back(num);
      |                 ^