#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i = 0; i < n; i++)
#define rep2(i, x, n) for(int i = x; i <= n; i++)
#define rep3(i, x, n) for(int i = x; i >= n; i--)
#define each(e, v) for(auto &e: v)
#define pb push_back
#define eb emplace_back
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sz(x) (int)x.size()
using ll = long long;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;
const int MOD = 1000000007;
//const int MOD = 998244353;
const int inf = (1<<30)-1;
const ll INF = (1LL<<60)-1;
template<typename T> bool chmax(T &x, const T &y) {return (x < y)? (x = y, true) : false;};
template<typename T> bool chmin(T &x, const T &y) {return (x > y)? (x = y, true) : false;};

struct io_setup{
    io_setup(){
        ios_base::sync_with_stdio(false);
        cin.tie(NULL);
        cout << fixed << setprecision(15);
    }
} io_setup;

bool judge(vector<ll> v){
    vector<ll> u = v;
    sort(all(v));
    if(v[0] == v[1] || v[1] == v[2]) return false;
    return (u[1] == v[0] || u[1] == v[2]);
}

ll score(vector<ll> v){
    int N = sz(v);
    vector<ll> dp(N+1, 0);

    rep(i, N){
        chmax(dp[i+1], dp[i]);
        if(i+3 > N) continue;
        vector<ll> u = {v[i], v[i+1], v[i+2]};
        if(judge(u)){
            chmax(dp[i+3], dp[i]+v[i]);
        }
    }

    return dp[N];
}

int main(){
    int T; cin >> T;

    while(T--){
        int N; cin >> N;

        vector<ll> a(N), b(N), c(N);
        rep(i, N){
            cin >> a[i];
            b[(i+1)%N] = a[i];
            c[(i+2)%N] = a[i];
        }

        cout << max({score(a), score(b), score(c)}) << '\n';
    }
}