团建 参考代码

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

typedef long long LL;
const int maxn = 200000 + 100;
int n, m, u, v;
int c[maxn], d[maxn];
vector<int> G1[maxn], G2[maxn];
map<int, int> mp[maxn];

void dfs1(int root, int fa) {
    for (int pos : G1[root]) {
        if (pos == fa) {
            continue;
        }
        mp[root][c[pos]] = pos;
        dfs1(pos, root);
    }
}

int dfs2(int root, int fa, int other) {
    int mx = 0;
    map<int, int>::iterator it;
    for (int pos : G2[root]) {
        if (pos == fa) {
            continue;
        }
        it = mp[other].find(d[pos]);
        if (it != mp[other].end()) {
            mx = max(mx, dfs2(pos, root, it->second));
        }
    }
    return mx + 1;
}

int main() {
#ifdef ExRoc
    freopen("test.txt", "r", stdin);
#endif
    ios::sync_with_stdio(false);

    cin >> n >> m;
    for (int i = 1; i <= n; ++i) {
        cin >> c[i];
    }
    for (int i = 1; i <= m; ++i) {
        cin >> d[i];
    }
    for (int i = 1; i < n; ++i) {
        cin >> u >> v;
        G1[u].push_back(v);
        G1[v].push_back(u);
    }
    for (int i = 1; i < m; ++i) {
        cin >> u >> v;
        G2[u].push_back(v);
        G2[v].push_back(u);
    }
    dfs1(1, 1);
    if (c[1] != d[1]) {
        cout << 0 << endl;
        return 0;
    }
    cout << dfs2(1, 1, 1) << endl;

    return 0;
}