#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vll = vector<ll>;
using pll = pair<ll, ll>;
ll INF = 1000000000000;
int main() {
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  ll t;
  cin >> t;
  for (int test = 0; test < t; test++) {
    ll n;
    cin >> n;
    ll k;
    cin >> k;
    n /= 2;
    vector<pll> a(n);
    for (int i = 0; i < n; i++) {
      cin >> a.at(i).first;
    }
    for (int i = 0; i < n; i++) {
      cin >> a.at(n - 1 - i).second;
    }
    vll sum(2 * k + 10, 0);
    for (int i = 0; i < n; i++) {
      ll f = a.at(i).first;
      ll s = a.at(i).second;
      sum.at(f + s) -= 1;
      sum.at(f + s + 1) += 1;
      ll mn = min(f, s) + 1;
      ll mx = max(f, s) + k;
      sum.at(2) += 2;
      sum.at(mn) -= 2;
      sum.at(mn) += 1;
      sum.at(mx + 1) -= 1;
      sum.at(mx + 1) += 2;
    }
    ll ans = INF;
    for (int i = 2; i <= 2 * k; i++) {
      sum.at(i) += sum.at(i - 1);
      ans = min(ans, sum.at(i));
    }
    cout << ans << endl;
  }
}
