Submission #595716

#	Time	Username	Problem	Language	Result	Execution time	Memory
595716		penguinhacker	Meetings 2 (JOI21_meetings2)	C++17	4 / 100	4075 ms	5472 KiB

meetings2

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

#define ll long long
#define ar array

const int mxN=2e5;
int n, d[mxN], s[mxN], anc[mxN][18], ans[mxN+1], tin[mxN], t;
vector<int> adj[mxN];
set<ar<int, 2>> active;

void dfs(int u=0) {
	s[u]=1;
	tin[u]=t++;
	for (int i=1; i<18; ++i)
		anc[u][i]=anc[anc[u][i-1]][i-1];
	for (int v : adj[u])
		if (v!=anc[u][0]) {
			d[v]=d[u]+1, anc[v][0]=u;
			dfs(v);
			s[u]+=s[v];
		}
}

int lca(int u, int v) {
	if (d[u]>d[v])
		swap(u, v);
	for (int i=17; ~i; --i)
		if (d[v]-(1<<i)>=d[u])
			v=anc[v][i];
	if (u==v)
		return u;
	for (int i=17; ~i; --i)
		if (anc[u][i]!=anc[v][i])
			u=anc[u][i], v=anc[v][i];
	return anc[u][0];
}

int dist(int u, int v) {
	return d[u]+d[v]-2*d[lca(u, v)];
}

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cin >> n;
	for (int i=1; i<n; ++i) {
		int u, v;
		cin >> u >> v, --u, --v;
		adj[u].push_back(v);
		adj[v].push_back(u);
	}
	dfs();
	vector<ar<int, 2>> upd;
	for (int i=1; i<n; ++i)
		upd.push_back({s[i], i});
	sort(upd.begin(), upd.end());
	fill(ans, ans+n+1, 1);
	int best=1;
	for (int i=n/2; i; --i) {
		/*while(upd.size()&&upd.back()[0]>=i) {
			int u=upd.back()[1];
			upd.pop_back();
			if (n-s[u]>=i) {
				int v=u;
				for (int j=17; ~j; --j)
					if (n-s[anc[v][j]]>=i)
						v=anc[v][j];
				best=max(best, d[u]-d[v]+2);
			}
			auto it=active.lower_bound({tin[u]});
			if (it!=active.begin()) {
				--it;
				int v=(*it)[1];
				if (tin[u]+s[u]<=tin[v]+s[v])
					active.erase(it);
			}
			for (ar<int, 2> x : active)
				best=max(best, dist(u, x[1])+1);
			active.insert({tin[u], u});
		}*/
		for (int j=0; j<n; ++j) {
			for (int k=j; k<n; ++k) {
				int u=j, v=k;
				if (tin[u]>tin[v])
					swap(u, v);
				if (tin[v]+s[v]<=tin[u]+s[u]) {
					if (s[v]>=i&&n-s[u]>=i)
						best=max(best, d[v]-d[u]+2);
				} else {
					if (s[u]>=i&&s[v]>=i)
						best=max(best, dist(u, v)+1);
				}
			}
		}
		ans[2*i]=best;
	}
	//cout << active.size() << endl;
	for (int i=1; i<=n; ++i)
		cout << ans[i] << "\n";
	return 0;
}

• Subtask 1: 4 / 4
• Subtask 2: 0 / 16
• Subtask 3: 0 / 80