Submission #869287

#	Time	Username	Problem	Language	Result	Execution time	Memory
869287		NK_	Meetings 2 (JOI21_meetings2)	C++17	100 / 100	393 ms	51828 KiB

meetings2

// Success consists of going from failure to failure without loss of enthusiasm
#include <bits/stdc++.h>
 
using namespace std;
 
#define nl '\n'
#define pb push_back
#define pf push_front
 
#define mp make_pair
#define f first
#define s second
#define sz(x) int(x.size())
 
template<class T> using V = vector<T>;
using pi = pair<int, int>;
using vi = V<int>;
using vpi = V<pi>;
 
using ll = long long;
using pl = pair<ll, ll>;
using vpl = V<pl>;
using vl = V<ll>;
 
using db = long double;
 
template<class T> using pq = priority_queue<T, V<T>, greater<T>>;
 
const int MOD = 1e9 + 7;
const ll INFL = ll(1e17);
const int LG = 19;

int main() {
	cin.tie(0)->sync_with_stdio(0);

	int N; cin >> N;

	V<vi> adj(N); 
	for(int i = 0; i < N-1; i++) {
		int u, v; cin >> u >> v; --u, --v;
		adj[u].pb(v);
		adj[v].pb(u);
	}

	vi sub(N), X(N, MOD);
	function<void(int, int)> prep = [&](int u, int p) {
		sub[u] = 1;
		for(auto& v : adj[u]) if (v != p) {
			prep(v, u);
			X[u] = min(X[u], N - sub[v]);
			sub[u] += sub[v];
		}

		X[u] = min(X[u], sub[u]);
		// cout << "X " << X[u] << " " << u << endl;
	};

	prep(0, -1);

	vi dep(N); V<vi> up(N, vi(LG));
	function<void(int, int)> gen = [&](int u, int p) {
		up[u][0] = p; dep[u] = (u == p ? 0 : dep[p] + 1);
		for(int i = 1; i < LG; i++) up[u][i] = up[up[u][i-1]][i-1];	

		for(auto& v : adj[u]) if (v != p) gen(v, u);
	};

	auto jmp = [&](int u, int d) {
		for(int i = 0; i < LG; i++) if ((d >> i) & 1) u = up[u][i];
		return u;
	};

	auto lca = [&](int a, int b) {
		if (dep[a] < dep[b]) swap(a, b);
		a = jmp(a, dep[a] - dep[b]);
		if (a == b) return a;
		for(int i = LG - 1; i >= 0; i--) {
			if (up[a][i] != up[b][i]) {
				a = up[a][i], b = up[b][i];
			}
		}
		return up[a][0];
	};	

	auto dist = [&](int a, int b) { return dep[a] + dep[b] - 2 * dep[lca(a, b)]; };

	gen(0, 0);

	vi U(N); iota(begin(U), end(U), 0);
	sort(begin(U), end(U), [&](int a, int b) {
		return X[a] > X[b];
	});	

	int a = U[0], b = U[0], d = 0;
	vi ans(N, 1);
	for(int i = N / 2, cur = 0; i >= 1; i--) {
		while(cur < N && X[U[cur]] >= i) {
			// add U[cur];
			int x = U[cur]; 
			// cerr << "ADD " << x << endl;
			int xa = dist(x, a), xb = dist(x, b);
			if (d < xa) b = x, d = xa; 
			else if (d < xb) a = x, d = xb;
			cur++;
		}
		// cerr << "=> " << d << endl;
		ans[2 * i - 1] = d + 1;
	}	

	for(int i = 0; i < N; i++) cout << ans[i] << nl;


	exit(0-0);
} 	 

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