A_Mean_Inequality.cpp

#include <bits/stdc++.h>
using namespace std;

#define ar array
#define ll long long
#define ld long double
#define sza(x) ((int)x.size())
#define all(x) x.begin(), x.end()
#define revall(x) x.rbegin(), x.rend()
#define sortall(x) sort(all(x))

const int mod=1e9+7;
const int MAX_N = 1e5 + 5;
const ll MOD = 1e9 + 7;
const ll INF = 1e9;
const ld EPS = 1e-9;
#define revall(x) x.rbegin(), x.rend()
#define ALL(x) sort(x.begin(), x.end())
#define sortall(x) sort(all(x))
#define reverseall(x) reverse(all(x))
#define SCD(t) scanf("%d",&t)
#define SCLD(t) scanf("%ld",&t)
#define SCLLD(t) scanf("%lld",&t)
#define SCC(t) scanf("%c",&t)
#define SCS(t) scanf("%s",t)
#define SCF(t) scanf("%f",&t)
#define SCLF(t) scanf("%lf",&t)
#define MEM(a, b) memset(a, (b), sizeof(a))
#define FOR(i, j, k, in) for (int i=j ; i<k ; i+=in)
#define RFOR(i, j, k, in) for (int i=j ; i>=k ; i-=in)
#define REP(i, j) FOR(i, 0, j, 1)
#define RREP(i, j) RFOR(i, j, 0, 1)
#define rall(cont) cont.end(), cont.begin()
#define FOREACH(it, l) for (auto it = l.begin(); it != l.end(); it++)
#define IN(A, B, C) assert( B <= A && A <= C)
#define MP make_pair
#define PB push_back
#define INF (int)1e9
#define EPS 1e-9
#define MOD 1000000007
#define PI 3.1415926535897932384626433832795
#define read(type) readInt<type>()
const double pi=acos(-1.0);
#define ll long long
typedef pair<int, int> PII;
typedef vector<int> VI;
typedef vector<vector<ll>> VII;
typedef vector<pair<int,int>>VPII;
typedef vector<string> VS;
typedef vector<PII> VIII;
typedef vector<VI> VVI;
typedef queue<string> QS;
typedef map<int,int> MPII;
typedef set<int> SETI;
typedef multiset<int> MSETI;
typedef long int int32;
typedef unsigned long int uint32;
typedef long long int int64;
typedef unsigned long long int  uint64;
typedef priority_queue<int,vector<int>,greater<int>> PQIVIGI;
#define ff(a,b) for(int i=a;i<b;i++)
#define nl endl


/* clang-format off */

/* TYPES  */
#define ll long long
#define pii pair<int, int>
#define pll pair<long long, long long>
#define vvi vector<vector<int>>
#define vll vector<long long>
#define vd vector<double>
#define mii map<long,long>
#define MPC map<char,int> 
#define miid map<double,long>
#define si set<int>
#define sc set<char>
#define vi vector<int>

/* FUNCTIONS */
#define f1(i,s,e) for(long long int i=s;i<e;i++)
#define ff1(pass) for(long long int i=n-2;i>=0;--i)
#define For1(i,n) or(long long int i=0;i<n+1;++i)
#define cf(i,s,e) for(long long int i=s;i<=e;i++)
#define fo(i,s,e) for(long long int i=1;i<=n*n;i+=2)
#define FO(i,s,e) for(long long int i=2;i<=n*n;i+=2)
#define rf(i,e,s) for(long long int i=e-1;i>=s;i--)
#define pb push_back
#define eb emplace_back

/* PRINTS */
template <class T>
void print_v(vector<T> &v) { cout << "{"; for (auto x : v) cout << x << ","; cout << "\b}"; }

/* UTILS */
ll min(ll a,int b) { if (a<b) return a; return b; }
ll min(int a,ll b) { if (a<b) return a; return b; }
ll max(ll a,int b) { if (a>b) return a; return b; }
ll max(int a,ll b) { if (a>b) return a; return b; }
ll gcd(ll a,ll b) { if (b==0) return a; return gcd(b, a%b); }
ll lcm(ll a,ll b) { return a/gcd(a,b)*b; }
string to_upper(string a) { for (int i=0;i<(int)a.size();++i) if (a[i]>='a' && a[i]<='z') a[i]-='a'-'A'; return a; }
string to_lower(string a) { for (int i=0;i<(int)a.size();++i) if (a[i]>='A' && a[i]<='Z') a[i]+='a'-'A'; return a; }


void yes() { cout<<"YES\n"; }
void no() { cout<<"NO\n"; }




/*  All Required define Pre-Processors and typedef Constants */
typedef long int int32;
typedef unsigned long int uint32;
typedef long long int int64;
typedef unsigned long long int  uint64;

bool isprime(ll n)
{
    ll x=sqrt(n);
    for(int i=2;i<=x;i++)
    {if(n%i==0)return true;}
    return false;
}


// bool cmp(pair<int,int> &a,pair<int,int> &b){
//     if(a.first==b.first)return a.second>b.second;
//     return a.first<b.first;
// }
 

void two_D_PrifixSum() 
{
    //prefix sum in 2 D array
    int n,m;cin>>n>>m;
    int a[n][m],prefix[n][m];
    f1(i,0,n)
    {
        f1(j,0,m)
        {
            cin>>a[i][j];
        }
    }

    //create a prefix array
    f1(i,0,n)
    {
        f1(j,0,m)
        {
            prefix[i][j]=a[i][j];
            if(i-1>=0)prefix[i][j]+=prefix[i-1][j];
            if(j-1>=0)prefix[i][j]+=prefix[i][j-1];

            if(i-1>=0 and j-1>=0)
            {
                prefix[i][j]-=prefix[i-1][j-1];
            }
        }
    }
    int q;cin>>q;
    while(q--)
    {
        int i1,i2,j1,j2;cin>>i1>>i2>>j1>>j2;
    }
}


//Scanline algorithm
void scanlineAlgoritm()
{
    int n;cin>>n;
    int a[n];
    f1(i,0,n)cin>>a[i];

    int prefixSum[n+1];
    int q;cin>>q;
    while(q--)
    {
        int l,r,x;cin>>l>>r>>x;
        prefixSum[l]+=x;
        prefixSum[r+1]-=x;
    }
    int s=0;
    f1(i,0,n)
    {
        s+=prefixSum[i];
        a[i]+=s;
    }
    f1(i,0,n)cout<<a[i]<<" ";
}

void solve()
{
    int n;cin>>n;n=n*2;
    VI a(n);
    f1(i,0,n){cin>>a[i];}
    sort(a.begin(),a.end());
    f1(i,0,n/2)
    {cout<<a[n/2+i]<<" "<<a[i]<<" ";}
    cout<<nl;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
#ifndef ONLINE_JUDGE
freopen("input.txt","r",stdin); //file input.txt is opened in reading mode i.e "r"
freopen("output.txt","w",stdout);  //file output.txt is opened in writing mode i.e "w"
#endif
    int tc = 1;
    cin >> tc;
    for (int t = 1; t <= tc; t++) {
        // cout << "Case #" << t << ": ";
        solve();
        // two_D_PrifixSum();
        // scanlineAlgoritm();

    }
}