Submission #1197669

#	Time	Username	Problem	Language	Result	Execution time	Memory
1197669		A_M_Namdar	Newspapers (CEOI21_newspapers)	C++20	12 / 100	12 ms	22596 KiB

newspapers

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

const int N = 22;
int n, m, d[1 << N], adj[1 << N], par[1 << N];

void input() {
	cin >> n >> m;
	if (m != n - 1) {
		cout << "NO\n";
		exit(0);
	}
	for (int i = 0; i < n - 1; i++) {
		int u, v;
		cin >> u >> v;
		u--, v--;
		adj[1 << u] |= (1 << v);
		adj[1 << v] |= (1 << u);
	}
}

void solve() {
	if (n == 1) {
		cout << "YES\n" << 1 << '\n' << 1;
		return;
	}
	for (int mask = 1; mask < (1 << n); mask++) 
		if (__builtin_popcount(mask) > 1) 
			adj[mask] = adj[mask - (mask & -mask)] | adj[mask & -mask];
	memset(d, 63, sizeof d);
	d[(1 << n) - 1] = 0;
	queue<int> q;
	q.push((1 << n) - 1);
	while (!q.empty()) {
		int u = q.front();
		q.pop();
		int tmp = adj[u];
		for (int i = 0; i < n; i++) 
			if ((tmp >> i) & 1) 
				if (d[tmp ^ (1 << i)] > d[u] + 1) {
					par[tmp ^ (1 << i)] = u;
					d[tmp ^ (1 << i)] = d[u] + 1;
					q.push(tmp ^ (1 << i));
				}
	}
	if (d[0] > 1e9) 
		cout << "NO\n";
	else {
		cout << "YES\n" << d[0] << '\n';
		vector<int> vec;
		int p = 0;
		while (p != (1 << n) - 1) {
			vec.push_back(__builtin_ctz(adj[par[p]] ^ p));
			p = par[p];
		}
		for (int i = vec.size() - 1; i >= 0; i--) 
			cout << vec[i] + 1 << ' ';
	}
}

int main() {
	ios:: sync_with_stdio(0), cin.tie(0), cout.tie(0);
	input();
	solve();
}

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