import sys
import math
import collections
import bisect


# sys.setrecursionlimit(10000001)
INF = 10 ** 20
# MOD = 10 ** 9 + 7
MOD = 998244353


def ni(): return int(sys.stdin.buffer.readline())
def ns(): return map(int, sys.stdin.buffer.readline().split())
def na(): return list(map(int, sys.stdin.buffer.readline().split()))
def na1(): return list(map(lambda x: int(x)-1, sys.stdin.buffer.readline().split()))


# ===CODE===

def main():
    t = ni()
    for ti in range(t):
        n = ni()
        a = na()

        flg = [False]*n
        for i in range(n):
            nxt = (i+1) % n
            nnxt = (i+2) % n
            ta = [a[i], a[nxt], a[nnxt]]
            if len(set(ta)) == 3 and (ta[0] < ta[1] > ta[2] or ta[0] > ta[1] < ta[2]):
                flg[i] = True

        res = 0
        for i in range(3):
            dp = [0]*(n+3)
            for j in range(i, n-2+i):
                if flg[j]:
                    dp[j+3] = max(dp[j+3], dp[j]+a[j])
                dp[j+1] = max(dp[j+1], dp[j])
            res = max(res, max(dp))
        print(res)


if __name__ == '__main__':
    main()