answer.code: In lambda function:
answer.code:24:9: error: declaration of ‘int r’ shadows a parameter
   24 |     int r;
      |         ^
answer.code:20:31: note: ‘int r’ previously declared here
   20 |   auto query = [&](int l, int r) {
      |                           ~~~~^
answer.code: In instantiation of ‘main()::<lambda(auto:46&, int, int)> [with auto:46 = main()::<lambda(auto:46&, int, int)>]’:
answer.code:41:6:   required from here
answer.code:38:8: error: no match for call to ‘(main()::<lambda(auto:46&, int, int)>) (int&, int)’
   38 |     rec(l, m - 1);
      |     ~~~^~~~~~~~~~
answer.code:30:14: note: candidate: ‘template<class auto:46> main()::<lambda(auto:46&, int, int)>’
   30 |   auto rec = [&](auto& rec, int l, int r) {
      |              ^
answer.code:30:14: note:   template argument deduction/substitution failed:
answer.code:38:8: note:   candidate expects 3 arguments, 2 provided
   38 |     rec(l, m - 1);
      |     ~~~^~~~~~~~~~
answer.code:39:8: error: no match for call to ‘(main()::<lambda(auto:46&, int, int)>) (int, int&)’
   39 |     rec(m + 1, r);
      |     ~~~^~~~~~~~~~
answer.code:30:14: note: candidate: ‘template<class auto:46> main()::<lambda(auto:46&, int, int)>’
   30 |   auto rec = [&](auto& rec, int l, int r) {
      |              ^
answer.code:30:14: note:   template argument deduction/substitution failed:
answer.code:39:8: note:   candidate expects 3 arguments, 2 provided
   39 |     rec(m + 1, r);
      |     ~~~^~~~~~~~~~