#include <iostream>
#include <iomanip>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <climits>
#include <string>
#include <set>
#include <cmath>
#include <map>
#include <unordered_map>
#include <numeric>
#include <random>
#include <memory>
#include <chrono>
#include <functional>
#include <unordered_set>
#include <cstring>
#include <cassert>
#include <bitset>
#ifdef LOCAL
#include "debug.h"
#else
#define debug(x...)
#endif
//#define int ll
//#pragma GCC optimize("Ofast")


using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair <int, int> pii;
typedef pair <ll, ll> pll;
#define sz(x) int((x).size())

#ifndef LOCAL
    mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#else
    mt19937 rng(228);
#endif

const int N = 1e4 + 7;
const int inf = INT_MAX / 2;
const ll INF = LLONG_MAX / 3;
const int MOD = 998244353;
const ld eps = 1e-6;
const string cars[] = {"🚗", "🚕", "🚙"};



signed main() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
    cout << fixed << setprecision(9);
    ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);

    int q;
    cin >> q;

    while (q--) {
        int n, k;
        cin >> n >> k;

        vector < int > a(n);
        for (int& x : a) {
            cin >> x;
        }

        map < int, int > m;
        vector < int > b(n / 2), c(n / 2);
        for (int i = 0; i < n / 2; i++) {
            m[a[i] + a[n - i - 1]]++;
            b[i] = k + max(a[i], a[n - i - 1]);
            c[i] = min(a[i], a[n - i - 1]) + 1;
        }
        sort(b.begin(), b.end());
        sort(c.begin(), c.end());

        debug(b);
        debug(c);

        int ans = inf;
        for (auto [x, y] : m) {
            int cur = n / 2 - y;
            cur += lower_bound(b.begin(), b.end(), x) - b.begin();
            cur += c.end() - upper_bound(c.begin(), c.end(), x);
            debug(x, n / 2 - y, cur);
            ans = min(ans, cur);
        }
        cout << ans << "\n";
    }

    return 0;
}