#!/usr/bin/env python3 #coding:utf-8 import math import string from sys import stdin # import numpy as np # from matplotlib import pyplot as plt def main(): read=stdin.readline #edit here! t=int(read()) while t>0: t-=1 n=int(read()) a=list(map(int,read().split())) check=lambda a,b,c:a!=b and b!=c and c!=a and (a<b>c or a>b<c) res=0 ans=0 i=0 while i<n-2: if check (a[i],a[i+1],a[i+2]): ans+=a[i] i+=3 else : i+=1 i=0 while i<n-2: if check(a[(i+1)%n],a[(i+2)%n],a[(i+3)%n]): res+=a[(i+1)%n] i+=3 else: i+=1 ans=max(ans,res) res=0 i=0 while i<n-2: if check(a[(i+2)%n],a[(i+3)%n],a[(i+4)%n]): res+=a[(i+2)%n] i+=3 else: i+=1 ans=max(ans,res) print(ans) if __name__ == '__main__': main()