class SegTree:
    def __init__(self, init_val, ide_ele, segfunc):
        self.n = len(init_val)
        self.num = 1<<(self.n-1).bit_length()
        self.ide_ele = ide_ele
        self.segfunc = segfunc
        self.seg = [ide_ele]*2*self.num
        # set_val
        for i in range(self.n):
            self.seg[i+self.num] = init_val[i]
        # built
        for i in range(self.num-1, 0, -1):
            self.seg[i] = self.segfunc(self.seg[2*i], self.seg[2*i+1])

    def update(self, k, x):
        k += self.num
        self.seg[k] = x
        while k:
            k = k >> 1
            self.seg[k] = self.segfunc(self.seg[2*k], self.seg[2*k+1])

    def query(self, l, r):
        if r <= l:
            return self.ide_ele
        l += self.num
        r += self.num
        lres = self.ide_ele
        rres = self.ide_ele
        while l < r:
            if r & 1:
                r -= 1
                rres = self.segfunc(self.seg[r], rres)
            if l & 1:
                lres = self.segfunc(lres, self.seg[l])
                l += 1
            l = l >> 1
            r = r >> 1
        res = self.segfunc(lres, rres)
        return res

    def __str__(self): # for debug
        arr = [self.query(i,i+1) for i in range(self.n)]
        return str(arr)

import sys
import io, os
input = io.BytesIO(os.read(0,os.fstat(0).st_size)).readline

t = int(input())
for _ in range(t):
    n = int(input())
    A = list(map(int, input().split()))
    A = A+A
    dp = SegTree([0]*(2*n+1), 0, max)
    for i in range(1, 2*n-1):
        x = dp.query(max(0, i-n+4), i-1)
        if A[i-1] < A[i] > A[i+1] and A[i-1] != A[i+1]:
            dp.update(i+1, x+A[i-1])
        elif A[i-1] > A[i] < A[i+1] and A[i-1] != A[i+1]:
            dp.update(i+1, x+A[i-1])
    print(dp.query(0, dp.n))