Submission #785734

#	Time	Username	Problem	Language	Result	Execution time	Memory
785734		gagik_2007	Newspapers (CEOI21_newspapers)	C++17	4 / 100	13 ms	7500 KiB

newspapers

#include <bits/stdc++.h>
using namespace std;

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

#define ff first
#define ss second

ll ttt;
const ll INF=1e18;
const ll MOD=1e9+7;
const ll N=300007;
ll n,m,k;
vector<ll>g[N];
ll sz[N];
bool used[N];

void dfs(int v, int par=-1){
    // cout<<"YOO"<<endl;
    sz[v]=1;
    for(int to:g[v]){
        if(to!=par){
            dfs(to,v);
            sz[v]+=sz[to];
        }
    }
}

bool is_tree(int v, int par=-1){
    used[v]=true;
    for(int to:g[v]){
        if(to!=par){
            if(used[to])return false;
            if(!is_tree(to,v))return false;
        }
    }
    return true;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    // freopen("output.txt","w",stdout);
    // freopen("input.txt","r",stdin);
    cin>>n>>m;
    // if(m!=n-1)cout<<"NO\n";
    for(int i=0;i<m;i++){
        int x,y;
        cin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    for(int v=1;v<=n;v++){
        if(!used[v]&&!is_tree(v)){
            cout<<"NO\n";
            return 0;
        }
    }
    for(int v=1;v<=n;v++){
        dfs(v);
        int cnt=0;
        for(int to:g[v]){
            cnt+=(sz[to]>1);
        }
        if(cnt>2){
            cout<<"NO\n";
            return 0;
        }
    }
    cout<<"YES 1 1\n";
}

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