def f(a,b,c):
    if a!=b and b!=c and c!=a:
        if (b>a and b>c) or (b<a and b<c):
            return a
        else:
            return 0
    return 0
T = int(input())
for _ in range(T):
    N = int(input())
    A = list(map(int,input().split()))
    B = [A[-1]]+A[:-1]
    C = [A[-2],A[-1]]+A[:-2]
    A = [0]+A
    dpa = [0]*(N+1)
    dpa[3] = f(A[1],A[2],A[3])
    for i in range(4,N+1):
        dpa[i] = max(dpa[i-1],dpa[i-3]+f(A[i-2],A[i-1],A[i]))
    B = [0]+B
    dpb = [0]*(N+1)
    dpb[3] = f(B[1],B[2],B[3])
    for i in range(4,N+1):
        dpb[i] = max(dpb[i-1],dpb[i-3]+f(B[i-2],B[i-1],B[i]))
    C = [0]+C
    dpc = [0]*(N+1)
    dpc[3] = f(C[1],C[2],C[3])
    for i in range(4,N+1):
        dpc[i] = max(dpc[i-1],dpc[i-3]+f(C[i-2],C[i-1],C[i]))
    print(max(dpa[N],dpb[N],dpc[N]))