제출 #881965

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
881965		TAhmed33	Newspapers (CEOI21_newspapers)	C++98	60 / 100	147 ms	26836 KiB

newspapers

#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e3 + 25;
vector <int> adj[MAXN];
int n, m;
int dfs (int pos, int par, int dep = 0) {
	if (dep == 3) {
		return 1;
	}
	int cnt = 0;
	for (auto j : adj[pos]) if (j != par) cnt += dfs(j, pos, dep + 1);
	if (!dep) return cnt;
	return cnt >= 1;
}
int dist[1 << 21];
pair <int, int> par[1 << 21];
queue <int> cur;
const int inf = 1e9;
int adjmask[1 << 21];
int main () {
	cin >> n >> m;
	bool flag = 1;
	for (int i = 1; i <= m; i++) {
		int a, b;
		cin >> a >> b;
		if (a > b) swap(a, b);
		flag &= a + 1 == b;
		adj[a].push_back(b);
		adj[b].push_back(a);
	}
	if (m != n - 1) {
		cout << "NO\n";
		return 0;
	}
	if (flag) {
		cout << "YES\n";
		if (n == 1) {
			cout << "1\n1\n";
			return 0;
		}
		if (n == 2) {
			cout << "2\n2 2\n";
			return 0;
		}
		cout << 2 * (n - 2) << '\n';
		for (int i = 2; i < n; i++) cout << i << " ";
		for (int i = n - 1; i >= 2; i--) cout << i << " ";
		cout << '\n';
		return 0;
	}
	if (n <= 20) {
		for (int i = 1; i <= n; i++) {
			for (auto j : adj[i]) {
				adjmask[i] += 1 << j;
			}
		}
		for (auto &i : dist) i = inf;
		dist[(1 << (n + 1)) - 2] = 0;
		cur.push((1 << (n + 1)) - 2);
		par[(1 << (n + 1)) - 2].first = -1;
		while (!cur.empty()) {
			auto k = cur.front();
			cur.pop();
			vector <int> t;
			for (int i = 1; i <= n; i++) {
				if (k & (1 << i)) {
					t.push_back(i);
				}
			}
			for (auto i : t) {
				int newmask = 0;
				for (auto j : t) {
					if (j == i) continue;
					newmask |= adjmask[j];
				}
				if (dist[newmask] == inf) {
					dist[newmask] = 1 + dist[k];
					par[newmask].first = k;
					par[newmask].second = i;
					cur.push(newmask);
				}
			}
		}
		if (dist[0] == inf) {
			cout << "NO\n";
			return 0;
		}
		cout << "YES\n";
		vector <int> ret;
		int mask = 0;
		while (mask != (1 << (n + 1)) - 2) {
			ret.push_back(par[mask].second);
			mask = par[mask].first;
		}
		reverse(ret.begin(), ret.end());
		cout << (int)ret.size() << '\n';
		for (auto i : ret) cout << i << " ";
		cout << '\n';
		return 0;
	}
	for (int i = 1; i <= n; i++) {
		if (dfs(i, -1) >= 3) {
			cout << "NO\n"; return 0;
		}
	}
	cout << "YES\n";
	cout << "1\n1\n";
}

• Subtask 1: 12 / 12
• Subtask 2: 8 / 8
• Subtask 3: 40 / 80