#include<bits/stdc++.h>
#define endl        '\n'
#define F           first
#define S           second
#define pb          push_back
#define yes         cout<<"YES\n"
#define no          cout<<"NO\n"
#define all(x)      x.begin(),x.end()
#define allr(x)     x.rbegin(),x.rend()
#define error1(x)   cerr<<#x<<" = "<<(x)<<endl
#define error2(a,b) cerr<<"("<<#a<<", "<<#b<<") = ("<<(a)<<", "<<(b)<<")\n";
#define coutall(v)  for(auto &it: v) cout << it << " "; cout << endl;
using namespace std;
using ll = long long;
using ld = long double;

void solve() {
    ll n, cnt = 0;
    cin >> n;
    vector<ll> val(n + 1);
    for (int i = 1; i <= n; i++) {
        ll x; cin >> x;
        val[i] = x;
        if(x) ++cnt;
    }
    vector<set<ll>> g(n + 1);
    for(int i = 0; i + 1 < n; i++) {
        ll u, v; cin >> u >> v;
        g[u].insert(v);
        g[v].insert(u);
    }
    if(cnt == 0) {
        cout << 0 << endl;
        return;
    }

    priority_queue<ll> pq;
    for(int i = 1; i <= n; i++) {
        if(g[i].size() == 1 && val[i] == 0) pq.push(i);
    }
    while(pq.size()) {
        ll u = pq.top();
        ll v = *g[u].begin();
        pq.pop();
        if(g[v].size() == 1 && val[v] == 0) {
            pq.push(v);
        }
        g[u].clear();
        g[v].erase(u);
    }

    vector<ll> depth(n + 1, 0);
    auto dfs2 = [&](int u, int par, int d, auto&& self) -> void {
        depth[u] = d;
        for(auto &i: g[u]) {
            if(i == par) continue;
            self(i, u, d + 1, self);
        }
    };
    ll root = 1;
    priority_queue<pair<ll, ll>> pp;
    for(int i = 1; i <= n; i++) {
        if(g[i].size() == 1) {
            dfs2(i, -1, 0, dfs2);
            break;
        }
    }
    for(int i = 1; i <= n; i++) {
        if(g[i].size() == 1) pp.push({depth[i], i});
    }

    ll ans = 0;
    auto dfs = [&](int u, int par, int d, auto&& self) -> ll {
        ll mxD = d;
        for(auto &v: g[u]) {
            if(v == par) continue;
            // cout << u << " " << v << endl;
            ++ans;
            mxD = max(mxD, self(v, u, d + 1, self));
            ++ans;
        }
        return mxD;
        // cout << u << " => " << c << endl;
    };
    ll Ans = LLONG_MAX, T = 20;
    while(T-- && pp.size()) {
        ans = 0;
        ans -= dfs(pp.top().S, -1, 0, dfs);
        Ans = min(Ans, ans);
        // cout << pp.top().S << " = " << ans << endl;
        pp.pop();
    }
    if(Ans == LLONG_MAX) Ans = 0;
    cout << Ans << endl;
    return;
}

signed main() {
    ios::sync_with_stdio(false); cin.tie(0);
    int tc = 1;
    cin >> tc;
    for (int t = 1; t <= tc; t++) {
        // cout << "Case " << t << ": ";
        solve();
    }
    return 0;
}