Submission #714025

#	Time	Username	Problem	Language	Result	Execution time	Memory
714025		vovamr	Pastiri (COI20_pastiri)	C++17	100 / 100	808 ms	101964 KiB

pastiri

#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;
const int lg = 19;

ve<int> gr[N];
int d[N];
int up[N][lg];

inline void dfs(int v, int p) {
	up[v][0] = p;
	for (int i = 1; i < lg; ++i) up[v][i] = up[up[v][i - 1]][i - 1];
	for (const auto &to : gr[v]) {
		if (to == p) continue;
		d[to] = d[v] + 1;
		dfs(to, v);
	}
}

inline void solve() {
	int n, k;
	cin >> n >> k;
	for (int i = 1; i < n; ++i) {
		int v, u;
		cin >> v >> u, --v, --u;
		gr[v].pb(u), gr[u].pb(v);
	}
	dfs(0, 0);
	ve<pii> a(k);
	for (auto &[x, y] : a) {
		cin >> y;
		x = d[--y];
	}
	sort(all(a));
	reverse(all(a));

	ve<int> dist(n, -1);
	queue<int> q;

	for (const auto &[x, y] : a) {
		dist[y] = 0;
		q.push(y);
	}
	while (sz(q)) {
		int v = q.front();
		q.pop();
		for (const auto &to : gr[v]) {
			if (~dist[to]) continue;
			dist[to] = dist[v] + 1;
			q.push(to);
		}
	}

	ve<int> answer, used(n);

	function<void(int)> upd = [&](int v) {
		used[v] = 1;
		for (const auto &to : gr[v]) {
			if (used[to]) continue;
			if (dist[to] != dist[v] - 1) continue;
			upd(to);
		}
	};

	for (const auto &[x, y] : a) {
		if (used[y]) continue;

		int v = y;
		for (int i = lg - 1; ~i; --i) {
			if (dist[up[v][i]] == d[y] - d[up[v][i]]) {
				v = up[v][i];
			}
		}
		answer.pb(v + 1);
		upd(v);
	}
	
	cout << sz(answer) << '\n';
	for (const auto &x : answer) cout << x << " ";
}

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: 8 / 8
• Subtask 2: 18 / 18
• Subtask 3: 23 / 23
• Subtask 4: 51 / 51