CLMTRO_author.cpp

// CLMTRO
// Author: meooow

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

const long long INF = 1e15;
const int MAX_N = 5005;

int t, n, a[MAX_N], b[MAX_N];
long long k;
vector<int> g[MAX_N];
int sz[MAX_N];
vector<long long> dp0[MAX_N], dpa[MAX_N], dpb[MAX_N];

inline void imin(long long &x, long long y) { if (x > y) x = y; }

void dfs(int u, int p) {
    dp0[u] = {0, INF};
    dpa[u] = {INF, a[u]};
    dpb[u] = {INF, INF};
    sz[u] = 1;
    for (int v : g[u]) if (v != p) {
        dfs(v, u);
        vector<long long> d0, da, db;
        d0 = da = db = vector<long long>(sz[u] + sz[v] + 1, INF);
        for (int i = 0; i <= sz[u]; i++) {
            for (int j = 0; j <= sz[v]; j++) {
                imin(d0[i + j], dp0[u][i] + min(dp0[v][j], min(dpa[v][j], dpb[v][j])));
                imin(da[i + j], dpa[u][i] + dp0[v][j]);
                imin(db[i + j], dpa[u][i] - a[u] + b[u] + min(dpa[v][j] - a[v] + b[v], dpb[v][j]));
                imin(db[i + j], dpb[u][i] + min(dpa[v][j] - a[v] + b[v], min(dp0[v][j], dpb[v][j])));
            }
        }
        dp0[u] = d0, dpa[u] = da, dpb[u] = db;
        sz[u] += sz[v];
    }
}

int main() {
    ios_base::sync_with_stdio(false); cin.tie(nullptr);

    cin >> t;
    while (t--) {
        cin >> n >> k;
        for (int i = 1; i <= n; i++)
            cin >> a[i];
        for (int i = 1; i <= n; i++)
            cin >> b[i];
        for (int i = 0; i < n - 1; i++) {
            int u, v; cin >> u >> v;
            g[u].push_back(v);
            g[v].push_back(u);
        }

        dfs(1, 1);

        for (int i = n; i >= 0; i--) {
            if (min(dp0[1][i], min(dpa[1][i], dpb[1][i])) <= k) {
                cout << i << "\n";
                break;
            }
        }

        fill_n(g, n + 1, vector<int>());
    }

    return 0;
}