import sys;input = lambda: sys.stdin.readline().rstrip()
#import heapq
#from collections import deque
#import numpy as np
#from collections import Counter as cnt
#from collections import defaultdict as ddc
#from math import factorial as fct
#from math import gcd
#from bisect import bisect_left as bsl
#from bisect import bisect_right as bsr
#from itertools import accumulate as acc
#from itertools import combinations as cmb
#from itertools import permutations as pmt
#from itertools import product as prd
#from functools import reduce as red
#import sys
#sys.setrecursionlimit(10**9)  #再帰を多く使う(デフォルトは1000)


for _ in range(int(input())):
    n = int(input())
    A = list(map(int,input().split()))
    A += A[:2]
    K = [0]*n
    for i in range(n):
        S = A[i:i+3]
        if len(set(S)) == 3 and S[1] in {min(S), max(S)}:
            K[i] = S[0]
    DP = [0]*n
    DP[0] = K[0]
    DP[1] = max(K[:2])
    DP[2] = max(K[:3])
    for i in range(3, n):
        DP[i] = max(DP[i-1], DP[i-2], DP[i-3]+K[i])
    print(DP[-1])