#pragma GCC optimize("O3")
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <string>
#include <cstring>
#include <deque>
#include <list>
#include <queue>
#include <stack>
#include <vector>
#include <utility>
#include <algorithm>
#include <map>
#include <set>
#include <complex>
#include <cmath>
#include <limits>
#include <cfloat>
#include <climits>
#include <ctime>
#include <cassert>
#include <numeric>
#include <fstream>
#include <functional>
#include <bitset>
using namespace std;

using ll = long long;
using P = pair<int, int>;
using T = tuple<int, int, int>;

template <class T> inline T chmax(T &a, const T b) {return a = (a < b) ? b : a;}
template <class T> inline T chmin(T &a, const T b) {return a = (a > b) ? b : a;}

constexpr int MOD = 1e9 + 7;
constexpr int inf = 1e9;
constexpr long long INF = 1e18;

#define all(a) (a).begin(), (a).end()

int dx[] = {1, 0, -1, 0};
int dy[] = {0, 1, 0, -1};

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    int t; cin>>t;
    while(t--){
        int n; cin>>n;
        vector<int> a(n);
        for(int i=0; i<n; i++) cin>>a[i];

        vector<vector<int>> aa(3, vector<int>(n));
        for(int i=0; i<3; i++){
            for(int j=i; j<n+i; j++){
                aa[i][j - i] = a[j % n];
            }
        }

        ll ans = 0;
        for(int st=0; st<3; st++){
            vector<ll> dp(n + 10, 0);
            for(int i=0; i<n-2; i++){
                chmax(dp[i + 1], dp[i]);
                int idx1 = i, idx2 = (i + 1) % n, idx3 = (i + 2) % n;
                if(aa[st][idx1] == aa[st][idx2] || aa[st][idx1] == aa[st][idx3] || aa[st][idx2] == aa[st][idx3]) continue;
                if(!((aa[st][idx1] < aa[st][idx2] && aa[st][idx2] > aa[st][idx3]) || (aa[st][idx1] > aa[st][idx2] && aa[st][idx2] < aa[st][idx3]))) continue;
                chmax(dp[i + 4], dp[i] + aa[st][idx1]);
            }
            chmax(ans, *max_element(all(dp)));
        }

        cout << ans << endl;
    }

    return 0;
}