minmax value + count

template <typename InputIterator, typename Predicate>
auto minmax_element(InputIterator first, InputIterator last, Predicate pred)
 -> std::pair<std::pair<decltype(*first), unsigned>, std::pair<decltype(*first), unsigned>>
{
    auto min_elem = *first;
    auto max_elem = *first;
    unsigned min_n = 0;
    unsigned max_n = 0;

    for (auto it = first; it != last; ++it) {
        auto const& n = *it;
        if (n < min_elem) {
            min_elem = n;
            min_n    = 1;
        } else if (!(min_elem < n)) {
            ++min_n;
        }

        if (max_elem < n) {
            max_elem = n;
            max_n    = 1;
        } else if (!(n < max_elem)) {
            ++max_n;
        }
    }

    return std::make_pair(
        std::make_pair(min_elem, min_n), std::make_pair(max_elem, max_n));
}

template <typename InputIterator>
auto minmax_element(InputIterator first, InputIterator last) {
    return ::minmax_element(first, last, std::less<decltype(*first)> {});
}

template <typename T>
auto minmax_element(std::initializer_list<T> const& list) {
    return ::minmax_element(std::begin(list), std::end(list));
}

void main() {
    minmax_element({10}); // ((10, 1), (10, 1))
    minmax_element({10, 10}); // ((10, 2), (10, 2))
    minmax_element({10, 1}); // ((1, 1), (10, 1))
    minmax_element({1, 10}); // ((1, 1), (10, 1))
    minmax_element({10, 1, 10}); // ((1, 1), (10, 2))
    minmax_element({10, 10, 6, 7, 1, 1, 11}); // ((1, 2), (11, 1))
    minmax_element({10, 1, 1, 0, 10, 10, 11}); // ((0, 1), (11, 1))
}