/in/foo.cc: In function 'int main()':
/in/foo.cc:25:16: error: invalid type argument of unary '*' (have '__gnu_cxx::__alloc_traits<std::allocator<long long int>, long long int>::value_type' {aka 'long long int'})
   25 |         ll l = *sub.back(), r = x[n] - x[1];
      |                ^~~~~~~~~~~
/in/foo.cc:26:20: error: 'r' was not declared in this scope
   26 |         while(l <= r) {
      |                    ^