t = int(input())
for _ in range(t):
    n = int(input())
    a = list(map(int,input().split()))
    a = a+a[:2]
    dp = [0]*(n+5)
    for i in range(n):
        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])
    print(max(dp))