結果

問題 No.2115 Making Forest Easy
ユーザー kwm_t
提出日時 2022-10-29 17:43:25
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 555 ms / 2,000 ms
コード長 3,972 bytes
コンパイル時間 3,874 ms
コンパイル使用メモリ 268,320 KB
最終ジャッジ日時 2025-02-08 15:48:42
ジャッジサーバーID
（参考情報） 		judge2 / judge2
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 2
other AC * 50
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ソースコード

diff # 

#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
//using mint = modint1000000007;
//const int mod = 1000000007;
using mint = modint998244353;
const int mod = 998244353;
//const int INF = 1e9;
//const long long LINF = 1e18;
//const bool debug = false;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n-1); i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define endl "\n"
#define P pair<long long,long long>
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }
struct ReRooting {
	struct Edge {
		int to;
		Edge(int _to) :to(_to) {}
	};
	vector<int>a;
	vector<vector<Edge>>g;
	vector<vector<mint>>dp, ans;
	int sz;
	ReRooting(int _sz) :sz(_sz) {
		a.resize(sz);
		g.resize(sz);
		dp = vector<vector<mint>>(sz, vector<mint>(1001));
		ans = vector<vector<mint>>(sz, vector<mint>(1001));
	}
	void ReadGraph() {
		rep(i, sz - 1) {
			int a, b; cin >> a >> b; a--; b--;
			g[a].push_back({ b });
			g[b].push_back({ a });
		}
	}
	/*
	chi*chi
	chi*par
	*/
	// childs*child
	vector<mint> mergeChi(const vector<mint> &lh, const vector<mint> &rh) {//★★
		vector<mint> ret(1001);
		vector<mint> lsub = lh, rsub = rh;
		rep2(i, 1, 1001)rsub[0] += rsub[i];
		rep2(i, 1, lsub.size())lsub[i] = lsub[i - 1] + lh[i];
		rep2(i, 1, rsub.size())rsub[i] = rsub[i - 1] + rh[i];
		rep(i, ret.size()) ret[i] = lsub[i] * rsub[i];
		rrep2(i, 1, ret.size())ret[i] -= ret[i - 1];
		return ret;
	}
	// par*childs
	vector<mint> mergePar(const vector<mint> &lh, const vector<mint> &rh) {//★★
		vector<mint> ret(1001);
		vector<mint> lsub = lh, rsub = rh;
		rep2(i, 1, lsub.size())lsub[i] = lsub[i - 1] + lh[i];
		rep2(i, 1, rsub.size())rsub[i] = rsub[i - 1] + rh[i];
		rep(i, ret.size()) ret[i] = lsub[i] * rsub[i];
		rrep2(i, 1, ret.size())ret[i] -= ret[i - 1];
		return ret;
	}
	// par(部分木)*childs
	vector<mint> mergePar2(const vector<mint> &lh, const vector<mint> &rh) {//★★
		vector<mint> ret(1001);
		vector<mint> lsub = lh, rsub = rh;
		rep2(i, 1, 1001)rsub[0] += rsub[i];
		rep2(i, 1, lsub.size())lsub[i] = lsub[i - 1] + lh[i];
		rep2(i, 1, rsub.size())rsub[i] = rsub[i - 1] + rh[i];
		rep(i, ret.size()) ret[i] = lsub[i] * rsub[i];
		rrep2(i, 1, ret.size())ret[i] -= ret[i - 1];
		return ret;
	}
	void dfs(int v, int p = -1) {
		vector<mint>sub(1001);
		sub[0] = 1;
		for (auto e : g[v]) {
			if (p == e.to)continue;
			dfs(e.to, v);
			sub = mergeChi(sub, dp[e.to]);
		}
		dp[v][a[v]] = 1;
		dp[v] = mergePar(dp[v], sub);
	}
	void dfsR(int v, int p = -1) {
		ans[v] = dp[v];
		if (-1 != p) ans[v] = mergePar2(ans[v], dp[p]);
		vector<vector<mint>>vdata;
		for (auto e : g[v]) vdata.push_back(dp[e.to]);
		int sz = vdata.size();
		vector<vector<mint>>sumL(sz + 1, vector<mint>(1001)), sumR(sz + 1, vector<mint>(1001));
		sumL[0][0] = 1, sumR[0][0] = 1;
		rep(i, sz)sumL[i + 1] = mergeChi(sumL[i], vdata[i]);
		rep(i, sz)sumR[i + 1] = mergeChi(sumR[i], vdata[sz - i - 1]);
		for (int i = 0; i < g[v].size(); ++i) {
			auto e = g[v][i];
			if (p == e.to)continue;
			auto chi = mergePar(sumL[i], sumR[sz - (i + 1)]);
			vector<mint>sub(1001);
			sub[a[v]] = 1;
			dp[v] = mergePar(sub, chi);
			dfsR(e.to, v);
		}
	}
	void debug() {
		rep(i, sz) {
			rep(j, 10) cout << dp[i][j].val() << " ";
			cout << endl;
		}
		cout << endl;
	}
	void output() {
		mint ret = 0;
		rep(i, sz) rep(j, 1001) ret += ans[i][j] * j;
		cout << ret.val() << endl;
	}
	void solve() {
		rep(i, sz)cin >> a[i];
		ReadGraph();
		dfs(0);
		dfsR(0);
		output();
	}
};
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int n; cin >> n;
	ReRooting reroot(n);
	reroot.solve();
	return 0;
}
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