/* Problem URL: https://codeforces.com/problemset/problem/2034/D */

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template <class T, class comp = less<>>
using ordered_set = tree<T, null_type , comp , rb_tree_tag , tree_order_statistics_node_update>;

#define V vector

#define rmin(a, b) a = min(a, b)
#define rmax(a, b) a = max(a, b)

#define rep(i, lim) for (int i = 0; i < (lim); i++)
#define nrep(i, s, lim) for (int i = s; i < (lim); i++)

#define repv(i, v) for (auto &i : (v))
#define fillv(v) for (auto &itr_ : (v)) { cin >> itr_; }
#define sortv(v) sort(v.begin(), v.end())
#define all(v) (v).begin(), (v).end()

using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;

using ll = long long;

using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vvvvl = vector<vvvl>;

template<class v>
auto operator<<(ostream &os, const vector<v> &vec)->ostream& {
    os << vec[0];
    for (size_t i = 1; i < vec.size(); i++) {
        os << ' ' << vec[i];
    }
    os << '\n';
    return os;
}

template<class v>
auto operator>>(istream &is, vector<v> &vec)->istream& {
    for (auto &i : vec) {
        is >> i;
    }
    return is;
}

template<class v>
auto operator<<(ostream &os, const vector<vector<v>> &vec)->ostream& {
    for (auto &i : vec) {
        os << i[0];
        for (size_t j = 1; j < i.size(); j++) {
            os << ' ' << i[j];
        }
        os << '\n';
    }
    return os;
}

template<class v>
auto operator>>(istream  &is, vector<vector<v>> &vec)->istream& {
    for (auto &i : vec) {
        for (auto &j : i) {
            is >> j;
        }
    }
    return is;
}

const int oo = INT32_MAX >> 1;
const ll OO = INT64_MAX >> 1;


void pre()
{

}

#define TEST 1

void solve()
{
    int n;
    cin >> n;
    vi a(n);
    cin >> a;

    array<int, 3> c = {0, 0, 0};
    set<int> o;
    rep(i, n) {
        c[a[i]]++;
        if (a[i] == 1) {
            o.insert(i);
        }
    }

    V<pair<int, int>> ans;

    auto printans = [&]() {
        cout << ans.size() << '\n';
        repv(i, ans) {
            cout << i.first << ' ' << i.second << '\n';
        }
    };

    nrep(i, c[0], c[0] + c[1]) {
        if (a[i] == 1) {
            o.erase(i);
            continue;
        }
    }

    int val = -1;
    nrep(i, c[0], c[0] + c[1]) {
        if (o.empty()) {
            break;
        }

        if (a[i] != 1) {
            if (o.size() == 1) {
                val = i;
                break;
            }
            swap(a[*o.begin()], a[i]);
            ans.emplace_back(*o.begin() + 1, i + 1);
            o.erase(o.begin());
        }
    }

    set<int> t;
    set<int> z;
    rep(i, c[0]) {
        if (a[i] > 1) {
            t.insert(i);
        }
    }

    nrep(i, c[0] + c[1], n) {
        if (a[i] < 1){
            z.insert(i);
        }
    }

    int ch = c[0];
    if (!o.empty()) {
        ch = *o.begin();
    } else {
        if (t.empty() || z.empty()) {
            cout << "0\n";
            return;
        }

        ans.emplace_back(*t.begin() + 1, c[0] + 1);
        val = c[0];
        ch = *t.begin();
        t.erase(t.begin());
    }

    int now = ch > c[0];
    while (!t.empty() || !z.empty()) {
        if (now) {
            ans.emplace_back(*t.begin() + 1, ch + 1);
            ch = *t.begin();
            t.erase(t.begin());
            now ^= 1;
            continue;
        }

        ans.emplace_back(*z.begin() + 1, ch + 1);
        ch = *z.begin();
        z.erase(z.begin());
        now ^= 1;
    }

    ans.emplace_back(ch + 1, val + 1);

    printans();
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    pre();

    int t;
    (TEST && cin >> t) || (t = 1);
    while (t--) {
        solve();
    }
}