// This Code was made by Chinese_zjc_.
#include <bits/stdc++.h>
unsigned long long seed = std::chrono::system_clock::now().time_since_epoch().count();
std::mt19937_64 Rand(seed);
int T, n, m;
std::vector<int> a, ans;
bool any(int) { return true; }
void reverse(int pos) { ans.push_back(pos), std::reverse(a.begin() + pos, a.begin() + pos + m); }
void lshift(int pos) { reverse(pos + 1), reverse(pos); }
void rshift(int pos) { reverse(pos), reverse(pos + 1); }
bool check()
{
    for (int i = 0; i != n; ++i)
        if (a[i] != i)
            return false;
    return true;
}
void print()
{
    std::cout << ans.size() << std::endl;
    for (auto i : ans)
        std::cout << i << '\n';
    exit(0);
}
void NO() { std::cout << -1 << std::endl, exit(0); }
void submit() { check() ? print() : NO(); }
bool calc(bool check(int))
{
    bool res = false;
    for (int i = 0; i != n; ++i)
        if (check(i))
            for (int j = i; ++j != n;)
                if (check(j))
                    res ^= a[i] > a[j];
    return res;
}
void shifto(int pos, int val)
{
    if (val < 0)
        val += m + 1;
    int A = val, B = m + 1 - val;
    if (A & 1)
        A = INT_MAX;
    if (B & 1)
        B = INT_MAX;
    if (A == INT_MAX && B == INT_MAX)
        NO();
    if (A < B)
        for (int i = 0; i != A >> 1; ++i)
            rshift(pos);
    else
        for (int i = 0; i != B >> 1; ++i)
            lshift(pos);
}
void down(std::size_t lim)
{
    while (a.size() > lim)
    {
        int pos = std::find(a.begin(), a.end(), a.size() - 1) - a.begin();
        while (pos + m <= int(a.size()))
            reverse(pos), pos += m - 1;
        if (((a.size() - 1) ^ pos) & 1)
            reverse(a.size() - m), pos = a.size() * 2 - m - 1 - pos;
        if (int(a.size() + pos) / 2 >= m)
        {
            reverse((a.size() + pos + 1) / 2 - m);
            reverse(a.size() - m);
        }
        shifto(a.size() - m - 1, std::prev(a.end(), 1) - std::find(a.begin(), a.end(), a.size() - 1));
        a.pop_back();
    }
    n = a.size();
}
bool solve_0(int pos, bool check())
{
    if (check())
        return true;
    reverse(pos);
    if (check())
        return true;
    return false;
}
bool solve_1(int A, int B, bool check())
{
    for (int i = 0; i != n; ++i)
    {
        if (check())
            return true;
        reverse(A);
        if (check())
            return true;
        reverse(B);
    }
    return false;
}
void solve_2(void shifto(int, int))
{
    if (a.front() == 2)
        shifto(0, 1);
    shifto(1, std::prev(a.end(), 1) - std::find(a.begin(), a.end(), 2));
    if (((n - 3) ^ calc(any)) & 1)
        shifto(0, 1);
    for (int i = 3; i != n; ++i)
    {
        int pos = std::find(a.begin(), a.end(), i) - a.begin();
        if (pos == 0)
        {
            shifto(1, std::prev(a.end(), 2) - std::find(a.begin(), a.end(), i - 1));
            shifto(0, std::prev(a.end(), 2 + (i != n - 1 && ~m & 1)) - std::find(a.begin(), a.end(), i));
            shifto(1, std::prev(a.end(), 1) - std::find(a.begin(), a.end(), i));
        }
        else
        {
            shifto(1, std::prev(a.end(), 1) - std::find(a.begin(), a.end(), i));
            shifto(0, std::prev(a.end(), 2) - std::find(a.begin(), a.end(), i - 1));
        }
    }
    // for (int i = 0; i != n; ++i)
    //     std::cout << a[i] << " \n"[i + 1 == n];
}
namespace odd
{
    bool odd(int pos) { return pos & 1; }
    bool even(int pos) { return !odd(pos); }
    void shifto(int pos, int val)
    {
        static const int len = (m + 1) >> 1;
        if (val < 0)
            val += len;
        int A = val, B = len - val;
        if (A < B)
            for (int i = 0; i != A; ++i)
                ans.push_back(pos << 1), ans.push_back(pos << 1 | 1);
        else
            for (int i = 0; i != B; ++i)
                ans.push_back(pos << 1 | 1), ans.push_back(pos << 1);
        std::rotate(a.begin() + pos, a.begin() + pos + len - val, a.begin() + pos + len);
    }
    bool check_odd()
    {
        for (int i = 0; i != n; ++i)
            if (odd(i) && a[i] != i)
                return false;
        return true;
    }
    bool check_even()
    {
        for (int i = 0; i != n; ++i)
            if (even(i) && a[i] != i)
                return false;
        return true;
    }
    void bind()
    {
        for (int i = 0; i != n >> 1; ++i)
        {
            if (a[m + 1] == a[1] - 1)
                lshift(1);
            else
            {
                int v = a[1];
                ::shifto(0, a.begin() - std::find(a.begin(), a.end(), v - 1));
                ::shifto(1, a.begin() + 1 - std::find(a.begin(), a.end(), v));
                lshift(0);
            }
            // for (int i = 0; i != n; ++i)
            //     std::cout << a[i] << " \n"[i + 1 == n];
        }
    }
    void solve_2()
    {
        int pos = std::find(a.begin(), a.end(), 1) - a.begin();
        if ((pos + 2 == n ? a[1] : a[pos + 2]) != 3)
            reverse(1);
        bind();
        ::shifto(0, a.begin() - std::find(a.begin(), a.end(), 0));
    }
    void solve_3()
    {
        bool A = (m + 1) >> 2 & 1, B = (m - 1) >> 2 & 1;
        bool Odd = calc(odd), Even = calc(even);
        bool flag = false;
        for (int i = 0; i != 2 && !flag; ++i)
            for (int j = 0; j != 2 && !flag; ++j)
                if ((Odd ^ (i ? A : 0) ^ (j ? B : 0)) == 0 &&
                    (Even ^ (i ? B : 0) ^ (j ? A : 0)) == 0)
                {
                    if (i)
                        reverse(0);
                    if (j)
                        reverse(1);
                    flag = true;
                }
        if (!flag)
            return;
        bind();
        for (int i = n; i--;)
            if (odd(i))
                a.erase(a.begin() + i);
            else
                a[i] >>= 1;
        n = a.size();
        ::solve_2(shifto);
    }
}
signed main()
{
    std::ios::sync_with_stdio(false);
    std::cin >> T >> n >> m;
    a.resize(n);
    for (int i = 0; i != n; ++i)
        std::cin >> a[i], --a[i];
    if (m == 1)
        submit();
    if (m == n)
        solve_0(0, check) ? print() : NO();
    if (m + 1 == n)
        solve_1(0, 1, check) ? print() : NO();
    if (m & 1)
    {
        for (int i = 0; i != n; ++i)
            if ((a[i] ^ i) & 1)
                NO();
        if (m == 3)
        {
            for (int i = 0; i != n; ++i)
                for (int j = n - 3; j >= 0; --j)
                    if (a[j] > a[j + 2])
                        reverse(j);
            submit();
        }
        down(m + 3);
        if (n == m + 2)
            odd::solve_2();
        else
            odd::solve_3();
        submit();
    }
    else
    {
        down(m + 2);
        if (calc(any))
            reverse(0);
        solve_2(shifto);
        submit();
    }
    return 0;
}