T=int(input())
for i in range(T):
  N=int(input())
  A=list(map(int, input().split()))
  A=A+A
  B=A[1:]+A[:1]
  C=A[2:]+A[:2]
  a,b,c=0,0,0
  d=0
  for j in range(N):
    d-=1
    if A[j]!=A[j+1] and A[j+1]!=A[j+2] and A[j+2]!=A[j] and d<0:
      if min(A[j],A[j+1],A[j+2])==A[j+1] or max(A[j],A[j+1],A[j+2])==A[j+1]:
        a+=A[j]
        d=2 
  d=0
  for j in range(N):
    d-=1
    if B[j]!=B[j+1] and B[j+1]!=B[j+2] and B[j+2]!=B[j] and d<0:
      if min(B[j],B[j+1],B[j+2])==B[j+1] or max(B[j],B[j+1],B[j+2])==B[j+1]:
        b+=B[j]
        d=2
  d=0
  for j in range(N):
    d-=1
    if C[j]!=C[j+1] and C[j+1]!=C[j+2] and C[j+2]!=C[j] and d<0:
      if min(C[j],C[j+1],C[j+2])==C[j+1] or max(C[j],C[j+1],C[j+2])==C[j+1]:
        c+=C[j]
        d=2
  print(max(a,b,c))