Submission #532565

#	Time	Username	Problem	Language	Result	Execution time	Memory
532565		qwerasdfzxcl	Newspapers (CEOI21_newspapers)	C++14	0 / 100	1 ms	460 KiB

newspapers

#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
constexpr int INF = 1e9;
vector<int> adj[1010];
int dist[1010], n;
pair<int, int> par[1010];

int _relax(int msk){
    int ret = 0;
    for (int i=1;i<=n;i++) if (msk&(1<<(i-1))){
        for (auto &v:adj[i]) ret |= (1<<(v-1));
    }
    return ret;
}

int main(){
    int m;
    scanf("%d %d", &n, &m);
    if (m>n-1) {printf("NO\n"); return 0;}

    for (int i=0;i<m;i++){
        int x, y;
        scanf("%d %d", &x, &y);
        adj[x].push_back(y);
        adj[y].push_back(x);
    }

    int mx = (1<<n) - 1;
    fill(dist, dist+mx+1, INF);
    dist[mx] = 0;
    queue<int> q;
    q.push(mx);

    while(!q.empty()){
        int s = q.front(); q.pop();
        for (int i=0;i<n;i++){
            int v = s & (mx ^ (1<<i));
            v = _relax(v);
            if (dist[v]!=INF) continue;
            dist[v] = dist[s] + 1;
            par[v] = {s, i+1};
            q.push(v);
        }
    }

    if (dist[0]==INF) printf("NO\n");
    else{
        printf("YES\n");
        vector<int> ans;
        for (int cur = 0;cur!=mx;cur=par[cur].first) ans.push_back(par[cur].second);
        reverse(ans.begin(), ans.end());
        printf("%d\n", (int)ans.size());
        for (auto &x: ans) printf("%d ", x);
    }
    return 0;
}

Compilation message (stderr)

newspapers.cpp: In function 'int main()':
newspapers.cpp:20:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |     scanf("%d %d", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~~
newspapers.cpp:25:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   25 |         scanf("%d %d", &x, &y);
      |         ~~~~~^~~~~~~~~~~~~~~~~

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