Submission #827372

#	Time	Username	Problem	Language	Result	Execution time	Memory
827372		NK_	Newspapers (CEOI21_newspapers)	C++17	4 / 100	1 ms	468 KiB

newspapers

// 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 mp make_pair
#define f first
#define s second
#define sz(x) int(x.size())
 
template<class T> using V = vector<T>;
using vi = V<int>;
using ll = long long;
using pi = pair<int, int>;
using vpi = V<pi>;
using vl = V<ll>;

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

	if (M != N - 1) {
		cout << "NO" << nl;
		return 0;
	}

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

	vi leaf(N);

	int R = 0;
	function<void(int, int)> dfs = [&](int u, int p) {
		leaf[u] = 1;

		int ADJ = 0;
		for(auto& v : adj[u]) if (v != p) {
			leaf[u] = 0; dfs(v, u);
			if (!leaf[v]) ADJ++;
		}

		if (!leaf[u] && ADJ == 1) R = u;

		if (ADJ > 2) {
			cout << "NO" << nl;
			exit(0-0);
		}
	};

	dfs(0, -1);

	vi ans;
	function<void(int, int)> answer = [&](int u, int p) {
		bool has = 0;
		for(auto& v : adj[u]) if (v != p) {
			if (leaf[v]) { has = 1; continue; }
			else {
				dfs(v, u);
			}
		}

        ans.pb(u);
		if (has) ans.pb(u);
	};

	answer(R, -1);

	cout << "YES" << nl;
	cout << sz(ans) << nl;
	for(auto& x : ans) cout << x + 1 << " ";
	cout << nl;

	exit(0-0);
}					

• Subtask 1: 0 / 12
• Subtask 2: 4 / 8
• Subtask 3: 0 / 80