Method begin

cpp/icm/flat_iterator.hpp:29–35

    using iterator_category = std::random_access_iterator_tag;

    static flat_iterator begin(const std::vector<C>& containers, const std::vector<value_type>& offsets)
    {
        if (containers.empty()) {
            return flat_iterator();
        }
        return flat_iterator(containers, offsets, containers.begin(), containers.begin()->begin());
    }

    static flat_iterator end(const std::vector<C>& containers, const std::vector<value_type>& offsets)
    {