answer.code: In function ‘int max_score(int, int, int, int, const std::vector<int>&, const std::vector<int>&, const std::vector<int>&)’:
answer.code:52:5: error: ‘function’ was not declared in this scope
   52 |     function<void(int)> dfs2 = & {
      |     ^~~~~~~~
answer.code:4:1: note: ‘std::function’ is defined in header ‘<functional>’; did you forget to ‘#include <functional>’?
    3 | #include <algorithm>
  +++ |+#include <functional>
    4 | 
answer.code:52:14: error: expected primary-expression before ‘void’
   52 |     function<void(int)> dfs2 = & {
      |              ^~~~
answer.code:67:5: error: ‘dfs2’ was not declared in this scope; did you mean ‘dfs’?
   67 |     dfs2(X);
      |     ^~~~
      |     dfs