#include <bits/stdc++.h>
char *fs, *ft, buf[1 << 20];
inline long long read() {
  long long x = 0, f = 1;
  char ch =
      (fs == ft && (ft = (fs = buf) + fread(buf, 1, 1 << 20, stdin), fs == ft))
          ? 0
          : *fs++;
  ;
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = -1;
    ch = (fs == ft &&
          (ft = (fs = buf) + fread(buf, 1, 1 << 20, stdin), fs == ft))
             ? 0
             : *fs++;
    ;
  }
  while (ch >= '0' && ch <= '9') {
    x = x * 10 + ch - '0';
    ch = (fs == ft &&
          (ft = (fs = buf) + fread(buf, 1, 1 << 20, stdin), fs == ft))
             ? 0
             : *fs++;
    ;
  }
  return x * f;
}
using namespace std;
const long long N = 2e5 + 5;
const long long inf = 0x7fffffff;
const long long mod = 1e9 + 7;
const double eps = 1e-6;
long long a[N], sum[N << 1];
void add(long long l, long long r, long long x) {
  if (r < l) return;
  sum[l] += x;
  sum[r + 1] -= x;
}
signed main() {
  long long t;
  cin >> t;
  while (t--) {
    long long n, k;
    cin >> n >> k;
    for (long long i = 0; i <= 2 * k; i++) sum[i] = 0;
    for (long long i = 1; i <= n; i++) cin >> a[i];
    for (long long i = 1; i <= n / 2; i++) {
      long long aa = a[i], bb = a[n - i + 1];
      add(2, min(aa, bb), 2);
      add(min(aa, bb) + 1, aa + bb - 1, 1);
      add(aa + bb + 1, max(aa, bb) + k, 1);
      add(max(aa, bb) + k + 1, 2 * k, 2);
    }
    for (long long i = 1; i <= 2 * k; i++) sum[i] = sum[i] + sum[i - 1];
    long long res = inf;
    for (long long i = 2; i <= 2 * k; i++) res = min(sum[i], res);
    cout << res << '\n';
  }
}
