from collections import defaultdict

t = int(input())
for _ in range(t):
    n = int(input())
    A = list(map(int, input().split()))
    A += A
    Counter = defaultdict(int)
    Counter[0] = 0
    for i in range(n):
        if len(set(A[i:i + 3])) != 3:
            continue
        if A[i] > A[i + 1] < A[i + 2] or A[i] < A[i + 1] > A[i + 2]:
            Counter[A[i]] += A[i]
    Vals = list(Counter.values())
    print(max(Vals))