#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int f(int a , int b , int c){
    if(a == b || b == c || c == a){
        return 0;
    }
    if(b < a && b < c){
        return a;
    }
    if(b > a && b > c){
        return a;
    }
    return 0;
}

void solve(){
    int n;
    cin >> n;
    vector<int> a(n);
    for (int i = 0; i < n; ++i) {
        cin >> a[i];
    }
   for(int i = 0; i < n % 3 + 2; i++){
       a.push_back(a[i]);
   }
    long long res = 0;
    long long cost0 = 0 , cost1 = 0 , cost2 = 0;
    for (int i = 0; i < n; i++) {
        if(i % 3 == 0)cost0 += f(a[i] , a[i + 1] , a[i + 2]);
        if(i % 3 == 1)cost1 += f(a[i] , a[i + 1] , a[i + 2]);
        if(i % 3 == 2)cost2 += f(a[i] , a[i + 1] , a[i + 2]);
    }
    res = max({cost0 , cost1 , cost2});
    cout << res << endl;
}
int main() {
    int t;
    cin >> t;
    while(t--){
        solve();
    }
    return 0;
}