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

using ll = long long;
using P = pair<ll, ll>;
const ll INF = (1LL << 61);
ll mod = 998244353;
bool is_kadomatsu(ll a, ll b, ll c) {
	if (a == b || b == c || a == c)return false;
	if ((a < b && b > c) || (a > b && b < c))return true;
	else return false;
}
ll f(vector<ll> &A) {
	ll N = A.size();
	vector<ll>dp(N + 1);
	for (int i = 3; i <= N; i++) {
		dp[i] = dp[i - 1];
		if (is_kadomatsu(A[i - 3], A[i - 2], A[i - 1]))dp[i] = max(dp[i], dp[i - 3] + A[i - 3]);
	}
	return dp[N];
}
signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	ll T; cin >> T;
	for (int _ = 0; _ < T; _++) {
		ll N; cin >> N;
		vector<ll>A(N);
		for (int i = 0; i < N; i++) {
			cin >> A[i];
		}
		ll ans = 0;
		for (int i = 0; i < 3; i++) {
			vector<ll>now;
			for (int j = 0; j < N; j++) {
				now.push_back(A[(i + j) % N]);
			}
			ans = max(ans, f(now));
		}
		cout << ans << endl;
	}
	return 0;
}