#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define int ll
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define REP(i, n) FOR(i, 0, n)
#define REP1(i, n) FOR(i, 1, n+1)
#define RREP(i, n) for (int i = (n)-1; i >= 0; i--)
#define pii pair<int, int>
#define f first
#define s second
#define pb push_back
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) (int)((x).size())
#ifdef TOAD
#define IOS()
#else
#define IOS() ios::sync_with_stdio(0), cin.tie(0), cout.tie(0)
#endif
const ll maxn = 1e5+5;
const ll mod = 1e9+7;
const ll inf = 1ll<<60;
signed main(){
IOS();
int T; cin>>T;
while(T--){
int n; cin>>n;
vector<int> v(n), p(n);
REP(i, n){
cin>>v[i];
v[i]--;
p[v[i]] = i;
}
bool gg = false;
bool oo = false;
vector<int> specid;
REP(i, n/2){
if (v[i] < n/2){
if (v[n-i-1] + v[i] != n-1){
gg = 1;
break;
}
}
else{
oo ^= 1;
if (v[n-i-1] + v[i] != n-1){
gg = 1;
break;
}
swap(v[n-i-1], v[i]);
p[v[i]] = i;
specid.pb(i);
}
}
// matching of specid, swap each swapping
if (gg || oo){
cout<<-1<<endl;
continue;
}
vector<pii> ans;
for(int i = 0; i < SZ(specid); i += 2){
ans.pb({specid[i], n-specid[i+1]-1});
swap(v[specid[i]], v[specid[i+1]]);
p[v[specid[i]]] = specid[i];
p[v[specid[i+1]]] = specid[i+1];
}
REP(i, n/2){
if (v[i] == i) continue;
int pp = p[i];
ans.pb({i, pp});
swap(v[i], v[pp]);
p[v[i]] = i;
p[v[pp]] = pp;
}
cout<<SZ(ans)<<' '<<SZ(ans)<<endl;
for (auto pp:ans) cout<<pp.f+1<<' '<<pp.s+1<<endl;
}
}
