t = int(input())
for _ in range(t):
    n = int(input())
    A = list(map(int,input().split()))
    ans = 0
    for j in range(3):
        a = A[j:]+A[:j]
        dp = [0]*(n+5)
        for i in range(n-2):
            dp[i] = max(dp[i],dp[i-1])
            x = a[i:i+3]
            if len(set(x)) == 3 and (min(x) == x[1] or max(x) == x[1]):
                dp[i+3] = max(dp[i+3],dp[i]+a[i])
        ans = max(ans,max(dp))
    print(ans)