#include <bits/stdc++.h>
using namespace std;

#define fo(i, n) for (int i = 0; i < n; i++)
#define count(n) for (int i = 1; i <= n; i++)
#define ll long long int
#define l long int
#define ld long double
#define ia(arr, n) fo(i, n) cin >> arr[i]
#define mo % 1000000007
#define precise(x) fixed << setprecision(x)

int weightOfBinary(ll n)
{
    int ans = 0;
    while (n != 0)
    {
        n = n & (n - 1);
        ans++;
    }
    return ans;
}
template <typename T>
bool isSet(T n, int bit)
{
    if ((n >> (bit)) & 1)
    {
        return 1;
    }
    return 0;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int t;
    cin >> t;
    while (t--)
    {
        int n;
        cin >> n;
        ll a[n];
        bool nev = 0;
        if (n % 2 == 0)
        {
            nev = 1;
        }
        int ne = 0, no = 0;
        fo(i, n)
        {
            cin >> a[i];
            if (a[i] % 2 == 0)
            {
                a[i] = 0;
                ne++;
            }
            else
            {
                a[i] = 1;
                no++;
            }
        }
        if (abs(ne - no) <= 1)
        {
            int ans = 0;
            if (nev)
            {
                int a1 = 0, a2 = 0, d1 = -1, d2 = -1; // d1 is for EO, d2 is for OE
                fo(i, n)
                {
                    if (isSet(a[i] ^ i, 0) == 0) // Correct place for EO
                    {
                        if (d2 == -1)
                        {
                            d2 = i;
                        }
                        else
                        {
                            a2 += (i - d2);
                            d2 = -1;
                        }
                    }
                    else // Correct place OE
                    {
                        if (d1 == -1)
                        {
                            d1 = i;
                        }
                        else
                        {
                            a1 += (i - d1);
                            d1 = -1;
                        }
                    }
                }
                ans = min(a1, a2);
            }
            else
            {
                int d = -1;
                bool f = 1;
                if (no > ne)
                {
                    f = 0;
                }
                fo(i, n)
                {
                    if (isSet(((a[i] ^ i) ^ f), 0) == 0)
                    {
                        if (d == -1)
                        {
                            d = i;
                        }
                        else
                        {
                            ans += (i - d);
                            d = -1;
                        }
                    }
                }
            }
            cout << ans << "\n";
        }
        else
        {
            cout << "-1\n";
        }
    }
    return 0;
}