fn is_kadomatsu(a: &Vec<usize>) -> bool {
    if a[0] == a[1] || a[1] == a[2] || a[2] == a[0] { return false; }
    (a[0] < a[1] && a[1] > a[2]) || (a[0] > a[1] && a[1] < a[2])
}

fn solve() -> usize {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).ok();
    let n: usize = n.trim().parse().unwrap();
    let mut a = String::new();
    std::io::stdin().read_line(&mut a).ok();
    let a: Vec<usize> = a.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();

    let mut ret = 0usize;
    for start in 0..3 {
        let mut dp = vec![vec![0usize; 2]; n+3];
        for i in 0..n-2 {
            let kados = vec![a[start+i], a[(start+i+1)%n], a[(start+i+2)%n]];
            dp[i+1][0] = dp[i+1][0].max(dp[i][0]).max(dp[i][1]);
            if is_kadomatsu(&kados) {
                dp[i+2][1] = dp[i+2][1].max(dp[i][0] + kados[0]);
            }
        }
        ret = ret.max(dp.iter().map(|v| *v.iter().max().unwrap()).max().unwrap());
    }
    ret
}

fn main() {
    let mut t = String::new();
    std::io::stdin().read_line(&mut t).ok();
    let t: usize = t.trim().parse().unwrap();
    let mut result = Vec::with_capacity(t);
    for _ in 0..t {
        result.push(solve());
    }
    for &v in result.iter() {
        println!("{}", v);
    }
}