Submission #786217

#	Time	Username	Problem	Language	Result	Execution time	Memory
786217		Evirir	Newspapers (CEOI21_newspapers)	C++17	0 / 100	0 ms	340 KiB

newspapers

#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
//using namespace __gnu_pbds;

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2")
#define watch(x) cout<<(#x)<<"="<<(x)<<'\n'
#define mset(d,val) memset(d,val,sizeof(d))
#define cbug if(DEBUG) cout
#define setp(x) cout<<fixed<<setprecision(x)
#define sz(x) (int)(x).size()
#define all(x) begin(x), end(x)
#define forn(i,a,b) for(int i=(a);i<(b);i++)
#define fore(i,a,b) for(int i=(a);i<=(b);i++)
#define pb push_back
#define F first
#define S second
#define fbo find_by_order
#define ook order_of_key
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> ii;
typedef vector<ll> vi;
typedef vector<ii> vii;
//template<typename T>
//using pbds = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
void SD(int t=0){ cout<<"PASSED "<<t<<endl; }
ostream& operator<<(ostream &out, ii x){ out<<"("<<x.F<<","<<x.S<<")"; return out; }
template<typename T> void amax(T &a, T b){ a=max(a,b); }
template<typename T> void amin(T &a, T b){ a=min(a,b); }
struct Hash {
	static uint64_t splitmix64(uint64_t x) {
		// http://xorshift.di.unimi.it/splitmix64.c
		x += 0x9e3779b97f4a7c15;
		x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
		x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
		return x ^ (x >> 31);
	}
	size_t operator()(uint64_t x) const {
		static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
		return splitmix64(x + FIXED_RANDOM);
	}
};

const ll INF = ll(1e18);
const int MOD = 998244353;
const bool DEBUG = 0;
const int MAXN = 1005;
const int LG = 21;

int n,m;
vector<int> adj[MAXN];

void no()
{
	cout<<"NO\n";
}

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

	cin>>n>>m;
	forn(i,0,m)
	{
		int u,v; cin>>u>>v; u--; v--;
		adj[u].pb(v);
		adj[v].pb(u);
	}

	if (m != n - 1)
	{
		no();
		return 0;
	}

	if (n == 1)
	{
		cout<<"YES\n";
		cout<<1<<'\n';
		cout<<1<<'\n';
		return 0;
	}

	int rt = -1;
	forn(i,0,n)
	{
		if (sz(adj[i]) == 1)
		{
			rt = i;
			break;
		}
	}
	assert(rt != -1);
	rt = adj[rt][0];
	if (sz(adj[rt]) != n - 1)
	{
		no();
		return 0;
	}

	cout << "YES\n";
	cout << 2 << '\n';
	cout << rt + 1 << ' ' << rt + 1 << '\n';

	return 0;
}

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