gistfile1.cpp

template<typename T> using Index = typename T::iterator::difference_type;

template<typename T>
std::pair<typename T::iterator::difference_type, T> prefix_match(T a, T b)
{
  auto mismatch = std::mismatch(a.cbegin(), a.cend(), b.cbegin());
  auto index = std::distance(a.cbegin(), mismatch.first);

  return std::make_pair(index, T(a.cbegin(), mismatch.first));
}

template<typename T>
std::pair<Index<T>, T> prefix_match(std::vector<T> list)
{
  return std::accumulate(list.cbegin(), list.cend(),
                         std::make_pair(Index<T>(0), *list.cbegin()),
                         [](std::pair<Index<T>, T> a, T b)
                         {
                           return prefix_match(a.second, b);
                         });
}