#include <bits/stdc++.h>
// #include <algorithm>
// #include <queue>
// #include <map>
// #include <iostream>
// #include <string>
// #include <set>
#define endl '\n'

using namespace std;

using LL = long long;
using PII = pair<int, int>;
using i128 = __int128_t;
using ULL = unsigned long long;

const int INF = 0x3f3f3f3f, MOD = 1e9 + 7, N = 1e6 + 5;
const LL LINF = 0x3f3f3f3f3f3f3f3f;

struct node
{
    int val, idx;

    bool operator < (const struct node & W) const
    {
        if(val != W.val) return val < W.val;
        return idx > W.idx;
    }

    bool operator > (const struct node & W) const
    {
        if(val != W.val) return val > W.val;
        return idx < W.idx;
    }
}node;

void solve()
{
    int n, m;
    cin >> n >> m;

    if(n < m)
    {
        cout << -1 << endl;
        return;
    }
    
    vector<int> f(n), g(m), b(m);
    multiset<int> S;
    for(int i = 0; i < n; i ++ )
    {
        cin >> f[i];
    }
    for(int i = 0; i < m; i ++ ) cin >> b[i];

    sort(f.begin(), f.end());
    sort(b.begin(), b.end());

    for(int i = 0; i < n - m; i ++ )
    {
        S.insert(f[i]);
    }
    for(int i = 0; i < m; i ++ )
    {
        g[i] = f[n - m + i];
    }

    LL sum = 0;
    int idx = -1;
    for(int i = 0; i < m; i ++ ) 
    {
        if(g[i] > b[i])
        {
            cout << -1 << endl;
            return;
        }

        if(idx == -1 and b[i] != g[i]) idx = i;
        sum += b[i] - g[i];
    }

    if(sum > n - m)
    {
        cout << -1 << endl;
        return;
    }

    priority_queue<struct node, vector<struct node>, greater<struct node> > q;
    for(int i = 0; i < m; i ++ )
    {
        if(g[i] < b[i]) q.push({g[i], i});
    }

    // cout << sum << endl;
    vector<int> ans;
    int cnt = 0;
    int num = S.size();
    for(auto it = S.begin(); ; it = next(it))
    {
        if(it != S.begin() and (cnt >= n - m - sum or it == S.end()))
        {
            S.erase(prev(it));
            break;
        }

        bool ok = true;
        if(*it >= b[0])
        {
            cout << -1 << endl;
            return;
        }
        auto nxt = next(it);

        if((!q.empty() and *it == q.top().val) or (nxt != S.end() and *nxt == *it))
        {
            if(!q.empty() and *it + 1 > q.top().val)
            {
                ok = false;         
                auto [val, idx] = q.top();
                q.pop();
                
                // cout << "hh" << val << endl;
                ans.push_back(val);
                g[idx] ++ ;
                if(g[idx] < b[idx]) q.push({g[idx], idx});
                
                cnt -- ;
            }
            else
            {
                S.erase(nxt);
                S.insert(*it + 1);
            }
        }

        if(ok) ans.push_back(*it);
        cnt ++ ;
        if(it != S.begin())
        {
            S.erase(prev(it));
        }
        num -- ;
        // for(auto j : S) cout << j << ' ';cout << endl;cout << *it << endl;
    }

    // cout << "----" << endl;// return;
    
    int sz = S.size();
    
    while(!S.empty())
    {
        if(q.empty())
        {
            cout << -1 << endl;
            return;
        }
        
        auto [val, idx] = q.top();
        // cout << "hh" << val << ' ' << idx << endl;
        q.pop();
        
        ans.push_back(val);
        g[idx] ++ ;
        if(g[idx] < b[idx]) q.push({g[idx], idx});
        S.erase(S.begin());
        sz -- ;
    }
    
    cout << n - m << endl;
    for(auto it : ans) cout << it << ' ';
    cout << endl;
    // cout << "----" << endl;
}   

int main()
{
    // freopen("galactic.in", "r", stdin);
    ios::sync_with_stdio(false), cin.tie(nullptr);
    int T = 1; 
    cin >> T;

    while(T -- )
        solve();
    return 0;
}