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

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int T;
    cin >> T;
    while(T--){
        int n;
        cin >> n;
        vector<int> a(n);
        for(auto &&v : a) cin >> v;
        auto f = [&](int i, int j, int k){
            if(a[i] > a[j] && a[j] < a[k] && a[i] != a[k]) return a[i];
            if(a[i] < a[j] && a[j] > a[k] && a[i] != a[k]) return a[i];
            return 0;
        };
        ll ans = 0;
        for(int q = 0; q < 3; q++){
            vector<ll> dp(n + 1, -(1ll << 60));
            dp[0] = 0;
            for(int j = 0; j < n; j++){
                dp[j + 1] = max(dp[j + 1], dp[j]);
                if(j + 3 <= n) dp[j + 3] = max(dp[j + 3], dp[j] + f(j, j + 1, j + 2));
            }
            ans = max(ans, dp[n]);
            rotate(a.begin(), a.begin() + 1, a.end());
        }
        cout << ans << '\n';
    }
}