def solve(a):
  q=[0]*(n+1)
  for i in range(n):
    if i-2>=0:
      if len(set(a[i-2:i+1]))==3:
        if max(a[i-2:i+1])==a[i-1] or min(a[i-2:i+1])==a[i-1]:
          q[i]=q[i-3]+a[i-2]
    q[i]=max(q[i],q[i-1])
  return max(q)

T=int(input())
for _ in range(T):
  n=int(input())
  a=list(map(int,input().split()))
  print(max(solve(a),solve(a[1:]+a[:1]),solve(a[2:]+a[:2])))