t=int(input())
ans=[]
for _ in range(t):
  n=int(input())
  a_=list(map(int,input().split()))
  ansi=0
  for idx in range(3):# スタート位置
    dp=[0]*(n+1)
    a=a_[idx:]+a_[:idx]
    for i in range(2,n):
      if a[i-2]!=a[i-1]!=a[i] and a[i-2]!=a[i] and (a[i-2]<a[i-1]>a[i] or a[i-2]>a[i-1]<a[i]):
        dp[i+1]=max(dp[i+1],dp[i-2]+a[i-2])
    ansi=max(ansi,max(dp))
  ans.append(ansi)
print(*ans,sep='\n')