HappyCerberus

uint64_t top_three(const std::vector<std::string>& data) {
  auto by_elf = data |
	  // group by elf: range{range{string}}
      std::views::lazy_split(std::string{}) |
	  // sum up the calories for each elf: range{uint64_t}	
      std::views::transform([](const auto& elf) -> uint64_t {
          // std::string -> uint64_t
          auto to_unsigned = 
            [](const auto& in) { return std::stoull(in); };
          // make a view of uint64_t: range{string} -> range{uint64_t}