#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("YES");}else{puts("NO");}
#define MAX_N 200005

int isKadomatsu(int x, int y, int z){
    int res = 0;
    if(y < x && y < z && x != z) res = 1;
    if(y > x && y > z && x != z) res = 1;
    return res;
}

int main() {
    int T; cin >> T;
    rep(_,T){
        int n; cin >> n;
        ll b[n*2];
        rep(i,n){
            cin >> b[i];
            b[i+n] = b[i];
        }
        ll ans = 0;
        rep(loop, 3){
            ll a[n];
            rep(i,n){
                a[i] = b[i+loop];
            }
            ll dp[n] = {};
            srep(i,2,n){
                dp[i] = dp[i-1];
                if(isKadomatsu(a[i-2],a[i-1],a[i])){
                    if(i == 2) dp[i] = a[i-2];
                    else dp[i] = max(dp[i], dp[i-3] + a[i-2]);
                }
            }
            ans = max(ans, dp[n-1]);
        }
        cout << ans << endl;
    }
    return 0;
}