bool kado(int a, int b, int c) {
  return ((a<b&&b>c)||(a>b&&b<c))&&(a!=c);
}

int N;
ll A[200010];

ll solvep(int N, ll* A) {
  ll ans = 0;
  REP(i, N-2) {
    if (kado(A[i], A[i+1], A[i+2])) {
      ans += A[i];
      i += 2;
    }
  }
  return ans;
}

void solve() {
  rd(N);
  rd(A(N));
  A[N] = A[0];
  A[N+1] = A[1];
  A[N+2] = A[2];
  ll best = 0;
  best = max(best, solvep(N, A));
  best = max(best, solvep(N, A+1));
  best = max(best, solvep(N, A+2));
  wt(best);
}

{
  int T;
  rd(T);
  REP(i, T) {
    solve();
  }
}