#include<bits/stdc++.h>                   // below comment for pbds
#include<ext/pb_ds/assoc_container.hpp>   // to use it make ordered_set
#include<ext/pb_ds/tree_policy.hpp>       // all set fnct + = 1. order_of_key(x); //number 
#define ll long long                      //of element strictly smaller than it;
#define ld long double                    // 2. find_by_order(x),pointer el at x pos after sort use as s.f();
#define ordered_set tree<ll, null_type,less<ll>, rb_tree_tag,tree_order_statistics_node_update>
using namespace std;                 
using namespace __gnu_pbds;



int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.flush();
	ll t=1;
	cin>>t;
	while(t--)
	{
	ll n,k;
	cin>>n>>k;
	ll a[200001];
	for(ll i=1;i<=n;i++)
	{
		cin>>a[i];
		}
	ll ans=0;	
	ll In[200002];
	ll Ins[200001];
	ll S[200001];
	memset(S,0,sizeof(S));
	memset(Ins,0,sizeof(Ins));
	memset(In,0,sizeof(In));
	for(ll i=1;i<=n;i++)
	{
		Ins[a[i]]++;
		In[a[i]]++;
	}
	
	for(ll i=1;i<=n/2;i++)
	{
	ll s= a[i]+a[n-i+1];	
	S[s]++;
	}
	for(ll i=200000;i>=0 ;i--)
	{
	In[i]=In[i+1]+In[i]; // largerequal top  sum i;		
	}
	
	for(ll i=1;i<=200000;i++)
	{
	Ins[i]=Ins[i-1]+Ins[i]; // smaller than or equal top  sum i;		
	}
	
	ll A;
	ans = LLONG_MAX;
	for(ll i=1;i<=n/2;i++)
	{
		ll s = a[i]+a[n-i+1];
	
		 A = n-(S[s]*2);
		 A=A/2;
		
		 ll p = s - k;
	
		 if(p-1>=0)  
		 A = A + Ins[p-1];
		
		 ll xx = s;
		if(xx>0)
		 A=A+ In[xx] ;
		
		 ans = min(ans,A)	;
	//	 cout<<"A: "<<A<<endl;
	}
	
	
	
	cout<<ans<<endl;
	}
	
return 0;
}