Submission #576540

#	Time	Username	Problem	Language	Result	Execution time	Memory
576540		8e7	Newspapers (CEOI21_newspapers)	C++17	8 / 100	12 ms	468 KiB

newspapers

//Challenge: Accepted
#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
#ifdef zisk
void debug(){cout << endl;}
template<class T, class ... U> void debug(T a, U ... b){cout << a << " ", debug(b...);}
template<class T> void pary(T l, T r) {
	while (l != r) cout << *l << " ", l++;
	cout << endl;
}
#else
#define debug(...) 0
#define pary(...) 0
#endif
#define ll long long
#define maxn 1005
#define mod 998244353
#define pii pair<int, int>
#define ff first
#define ss second
#define io ios_base::sync_with_stdio(0);cin.tie(0);
vector<int> adj[maxn], g[maxn];

int getdep(int n, int par) {
	int ret = 1;
	for (int v:adj[n]) {
		if (v != par) {
			ret = max(ret, getdep(v, n) + 1);
		}
	}
	return ret;
}

bool path[maxn];
void getpath(int n, int par) {
	path[n] = 1;
	bool to = 0;
	for (int v:g[n]) {
		if (v != par && g[v].size() > 1) {
			getpath(v, n);
			to = 1;
			break;
		}
	}
	if (to == 0) {
		for (int v:g[n]) {
			if (v != par) {
				getpath(v, n);
				break;
			}
		}
	}
}
vector<int> ans;
int last = 0;
void solve(int n, int par) {
	ans.push_back(n);
	last = n;
	for (int v:g[n]) {
		if (v != par && !path[v]) {
			ans.push_back(v);
			ans.push_back(n);
		}
	}
	for (int v:g[n]) {
		if (v != par && path[v]) {
			solve(v, n);
		}
	}
}
int main() {
	io
	int n, m;
	cin >> n >> m;
	for (int i = 0;i < m;i++) {
		int u, v;
		cin >> u >> v;
		adj[u].push_back(v);
		adj[v].push_back(u);
	}
	if (m > n - 1) {
		cout << "NO\n";
		return 0;
	}
	vector<int> nodes;
	for (int i = 1;i <= n;i++) {
		int cnt = 0;
		for (int v:adj[i]) {
			if (getdep(v, i) >= 3) cnt++;
		}
		if (cnt > 2) {
			cout << "NO\n";
			return 0;
		}
		if (adj[i].size() > 1) {
			nodes.push_back(i);
			for (int v:adj[i]) {
				if (adj[v].size() > 1) {
					g[i].push_back(v);
				}
			}
		}
	}	
	cout << "YES\n";
	if (nodes.size() == 0) {
		ans.push_back(1);
		if (n > 1) ans.push_back(1);
	} else if (nodes.size() == 1) {
		ans.push_back(nodes[0]);	
		ans.push_back(nodes[0]);	
	} else {
		for (int i:nodes) {
			if (g[i].size() == 1 && g[g[i][0]].size() <= 2) {
				getpath(i, 0);
				solve(i, 0);
				break;
			}
		}
		solve(last, 0);
	}
	cout << ans.size() << "\n";
	for (int i:ans) cout << i << " ";
	cout << "\n";
}

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