#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef long double ld;
typedef vector<int> vi;
typedef pair<int,int> pii;
#define flash ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define pb push_back
#define MP make_pair
#define F first
#define S second

int main() {
flash;


int t; cin>>t;
while(t--){

    ll n,k; cin>>n>>k;
    ll i,j,x,y,z,N;
    
    ll a[n]; for(i=0;i<n;i++){cin>>a[i];}
    
    N = 2*k+1;
    ll b[N+1]; //elements to be replaced
    for(i=0;i<=N;i++){ b[i] = 0; }

    for(i=0;i<n/2;i++){

        x = min(a[i],a[n-i-1]);
        y = max(a[i],a[n-i-1]);
        
        z = a[i] + a[n-i-1];

        b[0] += 2;
        b[x+1] -= 1;
        b[z] -= 1;
        b[z+1] += 1;
        b[k+y+1] += 1;
    }

    ll sum=0 , ans=n+1;
    for(i=0;i<=N;i++){
        sum += b[i];
        ans = min(ans,sum);
    }
    cout<<ans<<endl;
}

    return 0;
}