| # | 제출 시각 | 아이디 | 문제 | 언어 | 결과 | 실행 시간 | 메모리 |
|---|---|---|---|---|---|---|---|
| 478707 | 2021-10-08T07:32:33 Z | CSQ31 | Newspapers (CEOI21_newspapers) | C++17 | 0 ms | 0 KB |
#include <bits/stdc++.h>
using namespace std;
const int MAXN = 3e5+1;
int cnt[MAXN+1];
#define pb push_back
#define sz(a) (int)(a.size())
typedef long long int ll;
typedef vector<vector<int>>vii;
vii adj(1111);
bool ok = 1,vis[1111];
void dfs(int v,int u){
vis[v] = 1;
for(int x:adj[v]){
if(x == u)continue;
if(vis[x])ok = 0;
else dfs(x,v);
}
}
int main()
{
//the graph must be a tree
//if have cycle then bob's possible space never decreases around the cycle
//how to solve when have tree?
//think about search space of bob
//each turn a on state becomes off and turn everything incident to it on
//alice can pick a node and off it
//can she make everything off?
int n,m;
cin>>n>>m;
for(int i=0;i<m;i++){
int v,u;
cin>>v>>u;
adj[v].pb(u);
adj[u].pb(v);
}
dfs(1,0);
if(ok)dfs2(1,0);
if(ok){
cout<<"YES"<<'\n';
cout<<2<<'\n';
cout<<1<<" "<<1;
}
else cout<<"NO";
}