for _ in range(int(input())):
    n = int(input())
    a = list(map(int, input().split()))
    a.append(a[0])
    a.append(a[1])
    ans = 0
    for k in range(3):
        dp = [0, 0, 0]
        for i in range(k, n - 2 + k):
            if a[i] != a[i+2] and (a[i+1] > max(a[i], a[i+2]) or a[i+1] < min(a[i], a[i+2])):
                dp = [
                    max(dp[0], dp[1]),
                    dp[2],
                    dp[0] + a[i]
                ]
            else:
                dp = [
                    max(dp[0], dp[1]),
                    dp[2],
                    0
                ]
        ans = max(ans, *dp)
    print(ans)