def is_Kadomatsu(a,b,c):
    if len({a,b,c})!=3:
        return False

    return b==max(a,b,c) or b==min(a,b,c)

T=int(input())

for _ in range(T):
    N=int(input())
    A=list(map(int,input().split()))
    Max=0

    for _ in range(3):
        DP=[0]*N

        for i in range(2,N):
            DP[i]=DP[i-1]
            if is_Kadomatsu(A[i-2],A[i-1],A[i]):
                DP[i]=max(DP[i],DP[i-3]+A[i-2])
        M=max(DP)
        Max=max(M,Max)

        A=A[1:]+[A[0]]
    print(Max)