#include <bits/stdc++.h>
using namespace std;
 
#define rep(i, a, b) for(int i = (a); i < (b); i++)
#define all(x) (x).begin(), (x).end()
#define vi vector<int>
#define pb push_back 
#define ll long long int
#define watch(x) cout<<(#x)<< "is" <<(x) <<endl
#define endl "\n"
#define vii vector<pair<int,int>>
#define f first
#define s second

template<typename T>
void output_vector(const vector<T> &v, bool add_one = false, int start = -1, int end = -1) {
    if (start < 0) start = 0;
    if (end < 0) end = int(v.size());
 
    for (int i = start; i < end; i++)
        cout << v[i] + (add_one ? 1 : 0) << (i < end - 1 ? ' ' : '\n');
}
 
bool isPrime(ll n) {
    if(n==2) return true;
    for ( ll i = 2; i * i <= n; ++ i) {
        if (n % i == 0) {
            return false;
        }
    }
    return true;
} 

// bool prime[ll n];
// void SieveOfEratosthenes(ll n)
// {
    
//     memset(prime, true, sizeof(prime));
 
//     for (ll p = 2; p * p <= n; p++)
//     {
//         if (prime[p] == true)
//         {
//             for (ll i = p * p; i <= n; i += p)
//                 prime[i] = false;
//         }
//     }
// }


  void solve()
  {
    int n;
    cin>>n;
    vi v(n);
   
    int even = 0;
    int odd = 0;
    rep(i,0,n){
        cin>>v[i];
        if(v[i]&1){
            odd++;
            v[i]=1;
        }
        else{
            even++;
            v[i]=0;
        }
    }
    // rep(i,0,n){
    //     cout<<v[i];
    // }
    if(n%2==0 && (even!=odd)){
        // cout<<even<<" "<<odd<<endl;
        cout<<-1<<endl;
        return;
    }
    if((n&1) and abs(even-odd)!=1){
        cout<<-1<<endl;
        return;
    }
    int ans = 0;
    for(int i = n-2; i>=0; i--){
        if(v[i]!=v[i+1]) continue;
        int j = i-1;
        while(j>=0){
            if(v[j]!=v[i]) break;
            else j--;
        }
        swap(v[i],v[j]);
        ans = ans + i - j;
    }
    cout<<ans<<endl;
    
}
int main()
{
  ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);


    int t; cin>>t;
    while(t--){
     solve();
    }
}