#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    int n, k;
    cin >> n >> k;
    int arr[n];
    for (int i = 0; i < n; i++) {
      cin >> arr[i];
    }
    long long int sum[n / 2];
    int j = n / 2;
    int i = j - 1;
    int mini[n / 2];
    int maxii[n / 2];
    for (; i >= 0 && j < n; i--, j++) {
      sum[i] = arr[i] + arr[j];
      mini[i] = min(arr[i], arr[j]);
      maxii[i] = max(arr[i], arr[j]);
    }
    sort(mini, mini + n / 2);
    sort(maxii, maxii + n / 2);
    int ans = INT_MAX;
    map<long long int, int> mp;
    for (int i = 0; i < n / 2; i++) {
      mp[sum[i]]++;
    }
    for (int i = 2; i <= 2 * k; i++) {
      int temp1 = n / 2, temp2 = 0;
      if (i <= k) temp1 = lower_bound(mini, mini + n / 2, i) - mini;
      if (i > k) {
        temp2 = lower_bound(maxii, maxii + n / 2, i - k) - maxii;
      }
      int n1 = n / 2 - temp1;
      int n2 = temp2;
      ans = min(ans, n1 + n2 + n / 2 - mp[i]);
    }
    cout << ans << endl;
  }
  return 0;
}
