import sys

sys.setrecursionlimit(10**7)
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int,sys.stdin.readline().rstrip().split())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LI2(): return list(map(int,sys.stdin.readline().rstrip()))
def S(): return sys.stdin.readline().rstrip()
def LS(): return list(sys.stdin.readline().rstrip().split())
def LS2(): return list(sys.stdin.readline().rstrip())


def is_kadomatsu(X):
    if X[0] != X[1] != X[2] != X[0] and (max(X) == X[1] or min(X) == X[1]):
        return True
    return False


T = I()
for _ in range(T):
    N = I()
    A = LI()
    ans = 0
    for k in range(3):
        X = A[k:]+A[:k]
        dp = [0]*(N+1)
        for i in range(3,N+1):
            dp[i] = dp[i-1]
            if is_kadomatsu(X[i-3:i]):
                dp[i] = max(dp[i],dp[i-3]+X[i-3])
        ans = max(ans,dp[-1])
    print(ans)