#include<bits/stdc++.h>
using namespace std;
#define forn(i,x,y,z) for(int i=x;i<y;i+=z)
#define form(i,x,y,z) for(int i=x;i>y;i+=z)
#define ll long long
#define gcd(a,b) (__gcd(a,b))
#define lcm(a,b) (a/gcd(a,b)*b)
#define fast_cin() ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(0);
#define pb push_back
#define n_solve() ll test_case;cin>>test_case;forn(i,0,test_case,1){solve();}
const ll MAXN = 2e5+5;
const ll MOD = 1e9+7;
const ll MAXn = 1e5 + 5;
void solve(){
ll n,d,m; cin>>n>>d>>m;
pair<ll,ll> task[m];
forn(i,0,m,1){
cin>>task[i].first;
task[i].second = i+1;
}
sort(task,task+m);
vector<vector<ll>> ans;
ll lo = 1, hi = m;
while(lo<hi){
ll mid = lo + (hi-lo)/2, request = 0,flag = 0,check = 0;
vector<vector<ll>> schedule(n+1);
forn(i,1,n+1,1){
forn(j,0,mid,1){
if(task[request].first > i ){
break;
}
if(task[request].first + d >= i ){
schedule[i-1].pb(task[request++].second);
}else{
check = 1;
break;
}
if(request == m){
flag = 1;
check = 1;
break;
}
}
if(check)
break;
}
if(flag){
hi = mid;
ans = schedule;
}
else{
lo = mid + 1;
}
}
cout<<lo<<endl;
forn(i,0,n,1){
for(auto &j:ans[i]){
cout<<j<<" ";
}
cout<<"0\n";
}
}
void fileio(string filename = ""){
if((ll)(filename.size())){
freopen((filename + ".in").c_str(), "r", stdin);
freopen((filename + ".out").c_str(), "w", stdout);
}
}
signed main(){
fileio();
fast_cin();
solve();
}
