//Author: Kevin
#include<bits/stdc++.h>
//#pragma GCC optimize("O2")
using namespace std;
#define ll long long
#define ull unsigned ll
#define pb emplace_back
#define mp make_pair
#define ALL(x) (x).begin(),(x).end()
#define rALL(x) (x).rbegin(),(x).rend()
#define srt(x) sort(ALL(x))
#define rev(x) reverse(ALL(x))
#define rsrt(x) sort(rALL(x))
#define sz(x) (int)(x.size())
#define inf 0x3f3f3f3f
#define pii pair<int,int>
#define lb(v,x) (int)(lower_bound(ALL(v),x)-v.begin())
#define ub(v,x) (int)(upper_bound(ALL(v),x)-v.begin())
#define uni(v) v.resize(unique(ALL(v))-v.begin())
#define longer __int128_t
void die(string S){puts(S.c_str());exit(0);}
int n;
vector<pii> G[1005];
int p[1005];
int dist[1005][1005];
void dfs(int u,int fa,int d,int *di)
{
	di[u]=d;
	for(auto pr:G[u])
	{
		int v=pr.first;
		if(v!=fa)
			dfs(v,u,d+1,di);
	}
}
vector<vector<int>> Answer;
int check()
{
	for(int i=1;i<=n;i++)
		if(p[i]!=i)
			return 0;
	return 1;
}
inline int sqr(int x){return x*x;}
int cost[1005];
int f[1005],g[1005];
pii ind[1005];
void dfs(int u,int fa)
{
	f[u]=-inf;
	g[u]=0;
	for(auto pr:G[u])
		if(pr.first!=fa)
		{
			dfs(pr.first,u);
			g[u]+=max(f[pr.first],g[pr.first]);
		}
	for(auto pr:G[u])
		if(pr.first!=fa)
		{
			int val=cost[pr.second]+g[u]-max(f[pr.first],g[pr.first])+g[pr.first];
			if(val>f[u])
			{
				f[u]=val;
				ind[u]=pr;
			}
		}
}
vector<int> Edges;
void construct(int u,int fa);
void constructF(int u,int fa);
void constructG(int u,int fa);
void construct(int u,int fa)
{
	if(f[u]>g[u]) constructF(u,fa);
	else constructG(u,fa);
}
void constructF(int u,int fa)
{
	Edges.pb(ind[u].second);
	swap(p[u],p[ind[u].first]);
	for(auto pr:G[u])
		if(pr.first!=fa)
			(pr==ind[u]?constructG:construct)(pr.first,u);
}
void constructG(int u,int fa)
{
	for(auto pr:G[u])
		if(pr.first!=fa)
			construct(pr.first,u);
}
void op()
{
	Edges.clear();
	for(int i=1;i<n;i++) cost[i]=0;
	for(int i=1;i<=n;i++)
		for(auto pr:G[i])
		{
			int j=pr.first;
			cost[pr.second]+=sqr(dist[i][p[i]])-sqr(dist[j][p[i]]);
		}
	dfs(1,0);
	construct(1,0);
	Answer.pb(Edges);
}
void solve()
{
	cin>>n;
	for(int i=1;i<=n;i++)
		G[i].clear();
	for(int i=1;i<=n;i++)
		cin>>p[i];
	for(int i=1;i<n;i++)
	{
		int u,v;
		cin>>u>>v;
		G[u].pb(v,i);
		G[v].pb(u,i);
	}
	for(int i=1;i<=n;i++)
		dfs(i,0,0,dist[i]);
	Answer.clear();
	while(!check())
		op();
	cout<<sz(Answer)<<'\n';
	for(auto arr:Answer)
	{
		cout<<sz(arr)<<" ";
		for(auto E:arr)
			cout<<E<<" ";
		cout<<'\n';
	}
}
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	int t;
	cin>>t;
	while(t--)
		solve();
	return 0;
}