comment

src/day3.cpp

@@ -34,6 +34,7 @@ int64_t solve(const std::string_view line, size_t cnt_to_activate) {
     return max_char_as_int;
   }
   const auto recur{solve(line.substr(max_char_idx + 1), cnt_to_activate - 1)};
+  // slightly hacky... integral concat better?
   return std::stoll(std::string(&max_char) + std::to_string(recur));
 }