D.cpp

// #pragma GCC optimize("Ofast,unroll-loops")
// #pragma GCC target("avx,avx2,fma")

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

#define ll long long
#define ull unsigned long long
#define dd double
#define ld long double
#define sl(n) scanf("%lld", &n)
#define si(n) scanf("%d", &n)
#define sd(n) scanf("%lf", &n)
#define pll pair <ll, ll>
#define pii pair <int, int>
#define mp make_pair
#define pb push_back
#define all(v) v.begin(), v.end()
#define inf (1LL << 62)
#define loop(i, start, stop, inc) for(ll i = start; i <= stop; i += inc)
#define for1(i, stop) for(ll i = 1; i <= stop; ++i)
#define for0(i, stop) for(ll i = 0; i < stop; ++i)
#define rep1(i, start) for(ll i = start; i >= 1; --i)
#define rep0(i, start) for(ll i = (start-1); i >= 0; --i)
#define ms(n, i) memset(n, i, sizeof(n))
#define casep(n) printf("Case %lld:", ++n)
#define pn printf("\n")
#define pf printf
#define EL '\n'
#define fastio std::ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);

const ll sz = 1005;
ll ara[sz], cnt[sz];
vector <int> ans;

ll calcMex()
{
    for(ll i = 0; ; i++) {
        if(cnt[i] == 0)
            return i;
    }
}

int main()
{
    ll t;
    cin >> t;
    while(t--) {
        ll n;
        sl(n);

        for0(i, n) {
            sl(ara[i]);
            cnt[ ara[i] ]++;
        }

        while(!is_sorted(ara, ara+n)) {
            ll mex = calcMex();
            if(mex < n) {
                cnt[ ara[mex] ]--;
                ara[mex] = mex;
                cnt[ ara[mex] ]++;

                ans.pb(mex);
            }
            else {
                ll idx;
                for0(i, n) {
                    if(ara[i] != i) {
                        idx = i;
                        break;
                    }
                }

                cnt[ ara[idx] ]--;
                ara[idx] = mex;
                cnt[mex]++;

                ans.pb(idx);
            }
        }

        pf("%lld\n", (ll)ans.size());

        for(ll i = 0; i < ans.size(); i++) {
            if(i != 0) pf(" ");
            pf("%d", ans[i]+1);
        }
        pn;

        ms(cnt, 0);
        ans.clear();
    }

    return 0;
}