Submission #659712

#	Time	Username	Problem	Language	Result	Execution time	Memory
659712		Sohsoh84	Newspapers (CEOI21_newspapers)	C++17	0 / 100	14 ms	29048 KiB

newspapers

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int, int> pll;

#define all(x)			(x).begin(),(x).end()
#define X			first
#define Y			second
#define sep			' '
#define endl			'\n'
#define debug(x)		cerr << #x << ": " <<  x << endl;

const ll MAXN = 20;

int n, m, dist[1 << MAXN], t[1 << MAXN];
vector<int> adj[MAXN];
vector<pll> badj[1 << MAXN];

inline int f(int mask, int v) {
	mask = (mask | (1 << v)) ^ (1 << v);
	vector<int> vec;

	int ans = 0;
	for (int i = 0; i < n; i++)
		if (mask & (1 << i))
			for (int u : adj[i])
				ans |= (1 << u);

	return ans;
}

int main() {
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	cin >> n >> m;
	if (m >= n) return cout << "NO" << endl, 0;

	for (int i = 1; i < n; i++) {
		int u, v;
		cin >> u >> v;
		adj[u - 1].push_back(v - 1);
		adj[v - 1].push_back(u - 1);
	}
	
	for (int mask = 1; mask < (1 << n); mask++)
		for (int i = 0; i < n; i++)
			badj[f(mask, i)].push_back({mask, i});

	memset(dist, 63, sizeof dist);
	queue<int> q;

	dist[0] = 0;
	q.push(0);

	while (!q.empty()) {
		int v = q.front();
		q.pop();

		for (auto [u, x] : badj[v]) {
			if (dist[u] > dist[v] + 1) {
				dist[u] = dist[v] + 1;
				t[u] = x;
				q.push(u);
			}
		}
	}

	int mask = (1 << n) - 1;
	if (dist[mask] > MAXN * MAXN) return cout << "NO" << endl, 0;

	cout << dist[mask] << endl;
	while (mask) {
		cout << t[mask] + 1 << sep;
		mask = f(mask, t[mask]);
	}

	cout << endl;
	return 0;
}

• Subtask 1: 0 / 12
• Subtask 2: 0 / 8
• Subtask 3: 0 / 80