template <typename Iterator, typename MatchType>
Iterator
parallel_find_impl(Iterator first,
                   Iterator last,
                   MatchType match,
                   std::atomic<bool>& done)
{
  try {
    unsigned long const length         = std::distance(first, last);
    unsigned long const min_per_thread = 25;
    if (length < (2 * min_per_thread)) {
      for (; (first != last) && !done.load(); ++first) {
        if (*first == match) {
          done = true;
          return first;
        }
      }
      return last;
    }
    else {
      Iterator const mid_point = first + (length / 2);
      std::future<Iterator> async_result =
          std::async(&parallel_find_impl<Iterator, MatchType>,
                     mid_point,
                     last,
                     match,
                     std::ref(done));
      Iterator const direct_result =
          parallel_find_impl(first, mid_point, match, done);
      return (direct_result == mid_point) ? async_result.get() : direct_result;
    }
  }
  catch (...) {
    done = true;
    throw;
  }
}

template <typename Iterator, typename MatchType>
Iterator
parallel_find(Iterator first, Iterator last, MatchType match)
{
  std::atomic<bool> done(false);
  return parallel_find_impl(first, last, match, done);
}