/* -*- coding: utf-8 -*-
 *
 * 1854.cc:  No.1854 Limited Bubble Sort - yukicoder
 */

#include<cstdio>
#include<algorithm>
 
using namespace std;

/* constant */

const int MAX_N = 500;
const int MAX_NN = MAX_N * MAX_N;

/* typedef */

/* global variables */

int ps[MAX_N], ops[MAX_NN];

/* subroutines */

void bsort(int l, int r, int &m) {
  for (int i = l; i < r; i++)
    for (int j = i; j + 1 < r && ps[j] != j; j++) {
      ops[m++] = j;
      swap(ps[j], ps[j + 1]);
    }
}

/* main */

int main() {
  int tn;
  scanf("%d", &tn);

  while (tn--) {
    int n;
    scanf("%d", &n);
    for (int i = 0; i < n; i++) scanf("%d", ps + i), ps[i]--;

    int m = 0;
    for (int i = 0; i < n;) {
      while (i < n && ps[i] == i) i++;
      if (i >= n) break;

      int minp = ps[i], maxp = ps[i];
      int j = i + 1;
      while (j < n && ps[j] != j) {
	minp = min(minp, ps[j]);
	maxp = max(maxp, ps[j]);
	j++;
      }

      if (minp != i || maxp != j - 1) {
	m = -1; break;
      }

      bsort(i, j, m);
      i = j;
    }

    printf("%d\n", m);
    if (m >= 0) {
      for (int i = 0; i < m; i++) {
	if (i) putchar(' ');
	printf("%d", ops[i] + 1);
      }
      putchar('\n');
    }
  }

  return 0;
}