Submission #528173

#	Time	Username	Problem	Language	Result	Execution time	Memory
528173		Rafi22	Newspapers (CEOI21_newspapers)	C++14	6 / 100	1086 ms	20352 KiB

newspapers

#include <bits/stdc++.h>

using namespace std;

#define endl '\n'
#define st first
#define nd second
#define pb push_back
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
#define ll long long
ll mod=1000000007;
int inf=1000000007;
ll infl=1000000000000000007;

vector<int>G[1007];
vector<int>res;
bool ok;

void dfs(int v,int o)
{
    bool was=0;
    for(auto u:G[v])
    {
        if(u==o) continue;
        if(sz(G[u])>1)
        {
            if(!was) dfs(u,v);
            else ok=0;
            was=1;
        }
    }
}

map<int,int>odw;
int n;

void bt(int m)
{
    odw[m]=1;
    for(int j=0;j<n;j++)
    {
        if((m&(1<<j))) continue;
        m+=(1<<j);
        int nm=0;
        for(int i=1;i<=n;i++)
        {
            bool is=0;
            for(auto u:G[i])
            {
                if(!(m&(1<<(u-1)))) is=1;
            }
            if(!is) nm+=(1<<(i-1));
        }
        if(!odw[nm]) bt(nm);
        m-=(1<<j);
    }
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int m,a,b;
    cin>>n>>m;
    if(m!=n-1)
    {
        cout<<"NO";
        return 0;
    }
    for(int i=0;i<n-1;i++)
    {
        cin>>a>>b;
      //  a=i+2;
     //   b=rand()%(i+1)+1;
     //   cout<<a<<" "<<b<<endl;
        G[a].pb(b);
        G[b].pb(a);
    }
    vector<int>ans;
    bool is=0;
    for(int i=1;i<=n;i++)
    {
        ok=1;
        res.clear();
        dfs(i,0);
        if(ok)
        {
            is=1;
        }
    }
    /*if(!is) cout<<"NO"<<endl;
    else
    {
        cout<<"YES"<<endl;
        cout<<1<<endl<<1<<endl;
        //for(auto x:ans) cout<<1<<" ";
    }*/
    bt(0);
    if(odw[(1<<n)-1])
    {
        cout<<"YES"<<endl<<1<<endl<<1<<endl;
    }
    else cout<<"NO";

    return 0;
}

Compilation message (stderr)

newspapers.cpp: In function 'int main()':
newspapers.cpp:82:10: warning: variable 'is' set but not used [-Wunused-but-set-variable]
   82 |     bool is=0;
      |          ^~

• Subtask 1: 6 / 12
• Subtask 2: 0 / 8
• Subtask 3: 0 / 80