#include <bits/stdc++.h>

using namespace std;
typedef long long ll;

void solve() {
    ll n;
    cin >> n;
    ll res = 0;
    ll low = LLONG_MAX, high = 0;
    ll x;
    for (ll i = 0; i < n; i++) {
        cin >> x;
        low = min(low, x);
        high = max(high, x);
        bool ok = false;
        if (low == 1 && high == n && i == 1)  ok = true;
        // d == 1
        else if (high == low + i && (low == 1 || high == n)) ok = true;
        else if (high == low + i && high == n - 1 && low == 2)  ok = true;
        // d == 2, 则必定是排列的一半
        else if (low == 1 && high == (n - (n % 2 == 0)) && high == (low + 2 * i)) ok = true;
        else if (low == 2 && high == (n - (n % 2 == 1)) && high == (low + 2 * i)) ok = true;
        if (ok) res++;
    }
    res--;
    cout << res << endl;
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    ll T;
    cin >> T;
    for (ll i = 0; i < T; i++)
        solve();
    return 0;
}