/*

流石に無限回見た気がします。
https://atcoder.jp/contests/abc280/tasks/abc280_h


*/


#include <bits/stdc++.h>
using namespace std;
using ll=long long;
const ll ILL=2167167167167167167;
const int INF=2100000000;
#define rep(i,a,b) for (int i=(int)(a);i<(int)(b);i++)
#define all(p) p.begin(),p.end()
template<class T> using _pq = priority_queue<T, vector<T>, greater<T>>;
template<class T> int LB(vector<T> &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> int UB(vector<T> &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> bool chmin(T &a,T b){if(b<a){a=b;return 1;}else return 0;}
template<class T> bool chmax(T &a,T b){if(a<b){a=b;return 1;}else return 0;}
template<class T> void So(vector<T> &v) {sort(v.begin(),v.end());}
template<class T> void Sore(vector<T> &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});}
bool yneos(bool a,bool upp=false){if(a){cout<<(upp?"YES\n":"Yes\n");}else{cout<<(upp?"NO\n":"No\n");}return a;}
template<class T> void vec_out(vector<T> &p,int ty=0){
    if(ty==2){cout<<'{';for(int i=0;i<(int)p.size();i++){if(i){cout<<",";}cout<<'"'<<p[i]<<'"';}cout<<"}\n";}
    else{if(ty==1){cout<<p.size()<<"\n";}for(int i=0;i<(int)(p.size());i++){if(i) cout<<" ";cout<<p[i];}cout<<"\n";}}
template<class T> T vec_min(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmin(ans,x);return ans;}
template<class T> T vec_max(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmax(ans,x);return ans;}
template<class T> T vec_sum(vector<T> &a){T ans=T(0);for(auto &x:a) ans+=x;return ans;}
int pop_count(long long a){int res=0;while(a){res+=(a&1),a>>=1;}return res;}
template<class T> T square(T a){return a * a;}

#include <atcoder/string>
#include <atcoder/segtree>
using F = pair<int, int>;
F op(F a, F b){
    return min(a, b);
}
F e(){
    return {INF, INF};
}

void solve();
// POP'N ROLL MUSIC / TOMOO
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int t = 1;
    cin >> t;
    rep(i, 0, t) solve();
}

void solve(){
    ll N, K;
    cin >> N >> K;
    vector<int> A(N);
    rep(i, 0, N) cin >> A[i];
    auto sa = atcoder::suffix_array(A, N);
    auto lcp = atcoder::lcp_array(A, sa);
    K -= 1;
    vector<int> ans;
    atcoder::segtree<F, op, e> seg(N - 1);
    rep(i, 0, N - 1) seg.set(i, {lcp[i], i});
    auto f = [&](auto self, int l, int r, int d) -> void {
        // cout << l << " " << r << " " << d << endl;
        if (l + 1 == r){
            int rem = (N - sa[l]) - d;
            if (K < rem){
                rep(i, 0, d + K + 1){
                    ans.push_back(A[i + sa[l]]);
                }
                K = ILL;
            }
            K -= rem;
            return;
        }
        auto tmp = seg.prod(l, r - 1);
        ll rem = tmp.first - d;
        rem *= (r - l);
        if (K < rem){
            rep(i, 0, d + K / (r - l) + 1){
                ans.push_back(A[i + sa[l]]);
            }
            K = ILL;
        }
        K -= rem;
        self(self, l, tmp.second + 1, tmp.first);
        self(self, tmp.second + 1, r, tmp.first);
    };
    f(f, 0, N, 0);
    vec_out(ans);
}