Submission #670555

#	Time	Username	Problem	Language	Result	Execution time	Memory
670555		vovamr	Hard route (IZhO17_road)	C++17	0 / 100	8 ms	12080 KiB

road

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define fi first
#define se second
#define ll long long
#define ld long double
#define sz(x) ((int)(x).size())
#define all(x) 	(x).begin(), (x).end()
#define pb push_back
#define mpp make_pair
#define ve vector
using namespace std;
using namespace __gnu_pbds;
template<class T> using oset = tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
const ll inf = 1e18; const int iinf = 1e9;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
template <typename T> inline bool chmin(T& a, T b) { return (a > b ? a = b, 1 : 0); }
template <typename T> inline bool chmax(T& a, T b) { return (a < b ? a = b, 1 : 0); }

const int N = 5e5 + 100;
ve<int> gr[N];
int dep[N];

pii dpd[N];
int dpu[N];

inline void dfs(int v, int p) {
	dep[v] = 0;
	dpd[v] = {0, 0};
	for (auto &to : gr[v]) {
		if (to == p) continue;
		dfs(to, v);
		chmax(dep[v], dep[to] + 1);
		chmax(dpd[v].se, dep[to] + 1);
		if (dpd[v].se > dpd[v].fi) swap(dpd[v].fi, dpd[v].se);
	}
}
inline void dfs_down(int v, int p) {
	if (v == p) dpu[v] = 0;
	else {
		chmax(dpu[v], 1 + dpu[p]);
		int len = (dpd[p].fi == dep[v] + 1 ? dpd[p].se : dpd[p].fi);
		chmax(dpu[v], 1 + len);
	}
	for (auto &to : gr[v]) {
		if (to == p) continue;
		dfs_down(to, v);
	}
}

pll answer = {-inf, 0};
inline pll mg(const pll &a, const pll &b) {
	if (a.fi > b.fi) return a;
	else if (a.fi < b.fi) return b;
	else return mpp(a.fi, a.se + b.se);
}
inline void dfs_ans(int v, int p) {
	int deg = 0;
	for (auto &to : gr[v]) {
		if (to == p) continue;
		++deg;
		dfs_ans(to, v);
	}

	ve<int> G;
	for (auto &to : gr[v]) {
		if (to == p) continue;
		G.pb(to);
	}
	sort(all(G), [&](const int &a, const int &b) {
		return dep[a] < dep[b];
	});
	if (deg <= 1) return;

	int m = sz(G);
	ve<int> pf(m);
	for (int i = 0; i < m; ++i) {
		pf[i] = dep[G[i]] + 1;
		if (i) chmax(pf[i], pf[i - 1]);
	}

	int cur_mx = 0;
	for (int sec = m - 2; ~sec; --sec) {
		pll cur = mpp( max(!sec ? 0 : pf[sec - 1], max(dpu[v], cur_mx)) * 1ll * (dep[G[sec]] + dep[G[m - 1]] + 2), 1 );
		answer = mg(answer, cur);
		chmax(cur_mx, dep[G[sec]] + 1);
	}

	if (m >= 3) {
		int mx = dep[G[m - 2]] + dep[G[m - 3]] + 2;
		ll c = mx * 1ll * max(dpu[v], dep[G[m - 1]] + 1);

		ll ways = 0;
		map<int,int> mp;
		for (int i = 0; i < m - 1; ++i) {
			ways += mp[mx - (dep[G[i]] + 1)];
			++mp[dep[G[i]] + 1];
		}
		answer = mg(answer, mpp(c, ways));
	}
}

inline void solve() {
	int n;
	cin >> n;
	for (int i = 1; i < n; ++i) {
		int v, u;
		cin >> v >> u, --v, --u;
		gr[v].pb(u), gr[u].pb(v);
	}
	int root = -1;
	for (int i = 0; i < n; ++i) {
		if (sz(gr[i]) >= 2) {
			root = i;
			break;
		}
	}
	if (!~root) return void(cout << 0 << " " << 1);
	dfs(root, root);
	dfs_down(root, root);
	dfs_ans(root, root);
	cout << answer.fi << " " << answer.se << '\n';
}

signed main() {
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	int q = 1; // cin >> q;
	while (q--) solve();
	cerr << fixed << setprecision(3) << "Time execution: " << (double)clock() / CLOCKS_PER_SEC << endl;
}

• Subtask 1: 0 / 19
• Subtask 2: 0 / 33
• Subtask 3: 0 / 48