Submission #519425

#	Time	Username	Problem	Language	Result	Execution time	Memory
519425		AmShZ	Newspapers (CEOI21_newspapers)	C++11	100 / 100	72 ms	5808 KiB

newspapers

//khodaya khodet komak kon
# include <bits/stdc++.h>

using namespace std;

typedef long long                                        ll;
typedef long double                                      ld;
typedef pair <int, int>                                  pii;
typedef pair <pii, int>                                  ppi;
typedef pair <int, pii>                                  pip;
typedef pair <pii, pii>                                  ppp;
typedef pair <ll, ll>                                    pll;

# define A                                               first
# define B                                               second
# define endl                                            '\n'
# define sep                                             ' '
# define all(x)                                          x.begin(), x.end()
# define kill(x)                                         return cout << x << endl, 0
# define SZ(x)                                           int(x.size())
# define lc                                              id << 1
# define rc                                              id << 1 | 1
# define fast_io                                         ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);

ll power(ll a, ll b, ll md) {return (!b ? 1 : (b & 1 ? a * power(a * a % md, b / 2, md) % md : power(a * a % md, b / 2, md) % md));}

const int xn = 1e3 + 10;
const int xm = - 20 + 10;
const int sq = 320;
const int inf = 1e9 + 10;
const ll INF = 1e18 + 10;
const ld eps = 1e-15;
const int mod = 998244353;
const int base = 257;

int n, m, H[xn], rt1, rt2, P[xn];
vector <int> adj[xn], masir, vec, ans;
bool mark[xn], flag;

void DFS(int v, int p = - 1){
	P[v] = p;
	mark[v] = true;
	for (int u : adj[v]){
		if (mark[u]){
			flag |= u != p;
			continue;
		}
		H[u] = H[v] + 1;
		DFS(u, v);
	}
}
void DFS2(int v, int p = - 1){
	flag |= 2 < H[v];
	for (int u : adj[v]){
		if (mark[u] || u == p)
			continue;
		if (mark[v] && 1 < SZ(adj[u])){
			vec.push_back(u);
			vec.push_back(v);
		}
		H[u] = H[v] + 1;
		DFS2(u, v);
	}
}

int main(){
	fast_io;

	cin >> n >> m;
	for (int i = 1; i <= m; ++ i){
		int v, u;
		cin >> v >> u;
		adj[v].push_back(u);
		adj[u].push_back(v);
	}
	if (n <= 2){
		cout << "YES\n";
		cout << n << endl;
		for (int i = 1; i <= n; ++ i)
			cout << 1 << sep;
		cout << endl;
		return 0;
	}
	DFS(1);
	if (flag)
		kill("NO");
	for (int i = 1; i <= n; ++ i)
		if (H[rt1] < H[i])
			rt1 = i;
	H[rt1] = 0;
	fill(mark, mark + n + 1, false);
	DFS(rt1);
	for (int i = 1; i <= n; ++ i)
		if (H[rt2] < H[i])
			rt2 = i;
	fill(mark, mark + n + 1, false);
	rt2 = P[rt2];
	while (rt2 != rt1){
		masir.push_back(rt2);
		rt2 = P[rt2];
	}
	for (int v : masir)
		mark[v] = true;
	for (int v : masir){
		vec.push_back(v);
		H[v] = 0;
		DFS2(v);
		if (flag)
			kill("NO");
	}
	for (int x : vec)
		ans.push_back(x);
	reverse(all(vec));
	for (int x : vec)
		ans.push_back(x);
	cout << "YES\n";
	cout << SZ(ans) << endl;
	for (int x : ans)
		cout << x << sep;
	cout << endl;
	

	return 0;
}

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