#include <array>
#include <algorithm>

constexpr auto min_dis(int a, int l)
{
    return std::min({l-a, a});
}

constexpr auto max_dis(int a, int l)
{
    return std::max({l-a, a});
}

template <class Container>
constexpr auto get_min_time(const Container &container, int l)
{
    Container a = container;
    auto itr1 = container.cbegin();
    auto itr2 = a.begin();
    for (; itr1 != container.cend(); ++itr1, ++itr2)
    {
        *itr2 = min_dis(*itr1, l);
    }
    return *std::max_element(a.cbegin(), a.cend());
}

template <class Container>
constexpr auto get_max_time(const Container &container, int l)
{
    Container a = container;
    auto itr1 = container.cbegin();
    auto itr2 = a.begin();
    for (; itr1 != container.cend(); ++itr1, ++itr2)
    {
        *itr2 = max_dis(*itr1, l);
    }
    return *std::max_element(a.cbegin(), a.cend());
}

int main()
{
    constexpr auto l = 10;
    constexpr std::array x = {2, 6, 7};
    constexpr auto min_time = get_min_time(x, l);
    constexpr auto max_time = get_max_time(x, l);

    static_assert(min_time == 4);
    static_assert(max_time == 8);
    return 0;
}