#include <bits/stdc++.h>
using namespace std;
const long long int INF = LLONG_MAX;
vector<long long int> v1;
vector<pair<long long int, long long int> > v2;
string s1, s2, s3;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long int a, b, c, d, e, f, i, j, k, cnt1 = 0, cnt2 = 0, sum1 = 0,
                                           sum2 = 0, chk1 = 0, chk2 = 0, T;
  cin >> T;
  while (T--) {
    cnt1 = 0;
    v1.clear();
    cin >> a >> b;
    vector<long long int> ara(b + b + 3, 0);
    for (i = 0; i < a; i++) {
      cin >> c;
      v1.push_back(c);
    }
    ara[0] = a;
    for (i = 0; i < a / 2; i++) {
      long long int mx = max(v1[i], v1[a - i - 1]);
      long long int mn = min(v1[i], v1[a - i - 1]);
      ara[mn + 1]--;
      ara[mx + mn]--;
      ara[mx + mn + 1]++;
      ara[mx + b + 1]++;
    }
    long long int ans = INT_MAX;
    for (i = 1; i <= b + b + 2; i++) {
      ara[i] += ara[i - 1];
      ans = min(ara[i], ans);
    }
    cout << ans << endl;
  }
  return 0;
}
