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BePhuongSuperSuwi
From TK4 - CHT
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#include<bits/stdc++.h>
#define task "main"
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
#define endl '\n'
//#define int long long
#define pb push_back
#define fi first
#define se second
#define ii pair<int,int>
#define iii pair<int,ii>
#define iv pair<ii, ii>
#define base 341
#define MASK(i) (1ll << i)
#define oo 2e9
using namespace std;
//using namespace __gnu_pbds;
const int maxn = 1e6 + 5;
const int lg = 18;
int n, k, val[maxn], h[maxn], par[maxn][lg + 2];
vector <int> g[maxn], c[maxn];
void dfs(int u, int p) {
for (int x : g[u]) {
if (x == p) continue;
h[x] = h[u] + 1;
par[x][0] = u;
dfs(x, u);
}
}
int lca(int u, int v) {
if (h[u] < h[v]) swap(u,v);
for (int i = lg; i >= 0; i--) {
if ((h[u] - h[v]) >= MASK(i)) u = par[u][i];
}
if (u == v) return u;
for (int i = lg; i >= 0; i--) {
if (par[u][i] != par[v][i]) {
u = par[u][i];
v = par[v][i];
}
}
return par[u][0];
}
void prelca() {
dfs(1, -1);
for (int j = 1; j <= lg; j++) {
for (int i = 1; i <= n; i++) {
par[i][j] = par[par[i][j-1]][j-1];
}
}
}
namespace giai2{
vector <int> adj[maxn];
int lim = 0;
vector <ii> ed;
int tin[maxn], tour[maxn], timer = 0;
struct HLD{
int sz[maxn], Head[maxn], Pos[maxn], Id[maxn], chain, timer = 0, h[maxn], par[maxn];
int st[maxn * 4];
void build(int id, int l, int r) {
st[id] = ++lim;
if (l == r) {
adj[st[id]].pb(val[tour[l]]);
ed.pb({st[id], val[tour[l]]});
// cout << st[id] << " " << val[tour[l]] << endl;
return;
}
int m = (l + r) / 2;
build(id * 2, l, m);
build(id * 2 + 1, m + 1, r);
adj[st[id]].pb(st[id * 2]);
adj[st[id]].pb(st[id * 2 + 1]);
ed.pb({st[id], st[id * 2]});
ed.pb({st[id], st[id * 2 + 1]});
// cout << st[id] << " " << st[id * 2] << endl;
// cout << st[id] << " " << st[id * 2 + 1] << endl;
}
void dfs(int u, int p) {
sz[u] = 1;
for (int x : g[u]) {
if (x == p) continue;
h[x] = h[u] + 1;
par[x] = u;
dfs(x, u);
sz[u] += sz[x];
}
}
void hld(int u, int p) {
if (!Head[chain]) {
Head[chain] = u;
}
Id[u] = chain;
Pos[u] = tin[u] = ++timer;
tour[timer] = u;
int nxt = 0;
for (int x : g[u]) {
if (x == p) continue;
if (nxt == 0 || sz[nxt] < sz[x]) nxt = x;
}
if (nxt) hld(nxt, u);
for (int x : g[u]) {
if (x == p || x == nxt) continue;
chain++;
hld(x, u);
}
}
void update(int id, int l, int r, int u, int v, int idx) {
if (u > r || v < l) return;
if (l >= u && r <= v) {
adj[idx].pb(st[id]);
ed.pb({idx, st[id]});
// cout << idx << " " << st[id] << endl;
return;
}
int m = (l + r) / 2;
update(id * 2, l, m, u, v, idx);
update(id * 2 + 1, m + 1, r, u, v, idx);
}
void upd(int u, int v, int idx) {
while (Id[u] != Id[v]) {
if (h[Head[Id[u]]] > h[Head[Id[v]]]) swap(u,v);
update(1,1,n,Pos[Head[Id[v]]], Pos[v], idx);
v = par[Head[Id[v]]];
}
if (h[u] > h[v]) swap(u,v);
update(1,1,n,Pos[u], Pos[v], idx);
}
void init() {
timer = 0;
dfs(1, -1);
chain = 1;
hld(1, -1);
build(1, 1, n);
}
} hld1;
int d[maxn], low[maxn], ssc[maxn], tplt, sz[maxn];
bool in[maxn];
stack <int> stk;
void dfs(int u) {
d[u] = low[u] = ++timer;
stk.push(u);
for (int x : adj[u]) {
if (d[x] == 0) {
dfs(x);
low[u] = min(low[u], low[x]);
} else if (!in[x]) {
low[u] = min(low[u], d[x]);
}
}
if (d[u] == low[u]) {
int p;
tplt++;
do{
p = stk.top();
in[p] = true;
ssc[p] = tplt;
if (p <= k)
sz[tplt]++;
stk.pop();
}while(p!=u);
}
}
bool ok[maxn];
bool ss(int x, int y) {
return tin[x] < tin[y];
}
void solve() {
for (int i = 1; i <= n; i++) c[val[i]].pb(i);
lim = k;
hld1.init();
// for (int i = 1; i <= n; i++) cout << tin[i] << endl;
// cout << lim << endl;
for (int i = 1; i <= k; i++){
sort(c[i].begin(), c[i].end(), ss);
for (int j = 0; j < c[i].size() - 1; j++) {
hld1.upd(c[i][j], c[i][j + 1], i);
// cout << i << " " << c[i][j] << " " << c[i][j + 1] << endl;
}
}
timer = 0;
for (int i = 1; i <= lim; i++) {
if (!d[i]) dfs(i);
}
// // cout << tplt << endl;
for (int u = 1; u <= lim; u++) {
for (int v : adj[u]) {
int l = ssc[u], r = ssc[v];
if (l != r) {
ok[l] = 1;
}
}
}
int mini = oo;
for (int i = 1; i <= tplt; i++) {
if (!ok[i]) {
mini = min(mini, sz[i] - 1);
//cout << "ssc " << i << " " << sz[i] << endl;
}
}
cout << mini;
}
}
main() {
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
if(fopen(task".inp","r")) {
freopen(task".inp","r",stdin);
freopen(task".out","w",stdout);
}
cin >> n >> k;
for (int i = 1; i < n; i++) {
int l, r;
cin >> l >> r;
g[l].pb(r); g[r].pb(l);
}
prelca();
for (int i = 1; i <= n; i++) {
cin >> val[i];
}
// giai2::solve();
giai2::solve();
// if (n <= 2000) giai1::solve();
// else giai2::solve();
}
