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(n-2):
      if a[i]!=a[i+1]!=a[i+2] and a[i]!=a[i+2] and (a[i]<a[i+1]>a[i+2] or a[i]>a[i+1]<a[i+2]):
        dp[i+3]=max(dp[i+3],dp[i]+a[i])
      dp[i+1]=max(dp[i+1],dp[i])
    ansi=max(ansi,max(dp))
  ans.append(ansi)
print(*ans,sep='\n')