제출 #766046

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
766046		MISM06	Mergers (JOI19_mergers)	C++14	70 / 100	62 ms	18304 KiB

mergers

//0 1 1 0 1
//0 1 0 0 1
//1 0 0 1 1
//0 1 1 0 1
#include <bits/stdc++.h>
#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx2")
 
using namespace std;
 
#define F 			first
#define S 			second
#define pb 			push_back
#define sze			size()
#define	all(x)		x.begin() , x.end()
#define wall__		cout << "--------------------------------------\n";
#define kids		int mid = (tl + tr) >> 1, cl = v << 1, cr = v << 1 | 1
#define file_io		freopen("input.cpp", "r", stdin); freopen("output.cpp", "w", stdout);
 
typedef long long ll;
typedef long double dl;
typedef pair < int , int > pii;
typedef pair < int , ll > pil;
typedef pair < ll , int > pli;
typedef pair < ll , ll > pll;
typedef pair < int , pii > piii;
typedef pair < ll, pll > plll;
 
 
const ll N = 1e5 + 10;
const ll mod = 1e9 + 7;
const ll inf = 2e16;
const ll INF = 1e9 + 10;
const ll lg = 32;
 
int n, k, a[N], timer, c[N], sub[N], ans, b[N];
int root, cnt[N], h[N],  st[N], en[N], ord[N];
int sum;
vector < int > g[N];
bitset < N > mark;
 
void dfs0 (int v, int p) {
	sub[v] = 1; st[v] = ++timer; ord[st[v]] = v;
	h[v] = 0;
	for (auto u : g[v]) {
		if (p == u) continue;
		dfs0(u, v);
		if (sub[u] > sub[h[v]]) h[v] = u;
		sub[v] += sub[u];
	}
	en[v] = timer;
}	

void dfs (int v, int p) { 

	sum = 0;
	for (auto u : g[v]) {
		if (u == p || u == h[v]) continue;
		dfs(u, v);
		for (int i = st[u]; i <= en[u]; i++) mark[a[ord[i]]] = 0;
		sum = 0;
		cnt[v] += cnt[u];
	}
	if (h[v]) {
		dfs(h[v], v); cnt[v] += cnt[h[v]];
		for (int i = st[v]; i < st[h[v]]; i++) {
			if (mark[a[ord[i]]] == 0) {
				mark[a[ord[i]]] = 1;
				sum += c[a[ord[i]]];
			}
		}
		for (int i = en[h[v]] + 1; i <= en[v]; i++) {
			if (mark[a[ord[i]]] == 0) {
				mark[a[ord[i]]] = 1;
				sum += c[a[ord[i]]];
			}
		}
	}
	if (mark[a[v]] == 0) {
		mark[a[v]] = 1;
		sum += c[a[v]];
	}
	
	if ((sum == sub[v] && v != root)) {
		b[v] = 1;
		++cnt[v];
	}
}

void dfs1(int v, int p) {
	if (b[v] == 1) {
		if (cnt[v] == 1 || cnt[v] == cnt[root]) ++ans;
	}
	for (auto u : g[v]) {
		if (u == p) continue;
		dfs1(u, v);
	}
}
 
void solve () {
 
	cin >> n >> k;
	for (int i = 1; i < n; i++) {
		int v, u; cin >> v >> u;
		g[v].pb(u); g[u].pb(v);
	}
	for (int i = 1; i <= n; i++) {
		cin >> a[i]; ++c[a[i]];
	}
	root = 1;
	for (int i = 2; i <= n; i++) {
		if (g[i].sze > g[root].sze) root = i;
	}
	dfs0(root, 0);
	dfs(root, 0);
	dfs1(root, 0);
	cout << (ans + 1) / 2 << '\n';
 
 
}
 
 
int main() {
	ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	int t = 1;
	// cin >> t;
	while (t--) {solve();}
    return 0;
}
/*
*/
//shrek will AC this;

• Subtask 1: 10 / 10
• Subtask 2: 24 / 24
• Subtask 3: 14 / 14
• Subtask 4: 22 / 22
• Subtask 5: 0 / 30