def solve():
  n=int(input())
  a=list(map(int,input().split()))
  a+=a[0:2]
  isK=[a[i]!=a[i+2]and((a[i]<a[i+1]and a[i+1]>a[i+2])or(a[i]>a[i+1]and a[i+1]<a[i+2])) for i in range(n)]
  ans=0
  for j in range(3):
    dp=[0]*4
    for i in range(n):
      res=dp[i%4]
      if i>=2and isK[j+i-2]and res<dp[(i+2)%4]+a[j+i-2]:
        res=dp[(i+2)%4]+a[j+i-2]
      dp[(i+1)%4]=res
    res=max(dp)
    if ans<res:
      ans=res
  print(ans)
def main():
  import sys
  input=sys.stdin.readline
  for _ in range(int(input())):
    solve()
main()