Submission #1285165

#	Time	Username	Problem	Language	Result	Execution time	Memory
1285165		stefanneagu	Newspapers (CEOI21_newspapers)	C++20	75 / 100	44 ms	4620 KiB

newspapers

#include <bits/stdc++.h>

using namespace std;

const int nmax = 1e5 + 1;

vector<int> adj[nmax];
int tata[nmax];
bool f[nmax];
bool viz[nmax];


pair<int, int> dfs(int i, int dad = 0) {
    pair<int, int> deep = {0, i};
    for (auto it : adj[i]) {
        if (it != dad) {
            tata[it] = i;
            pair<int, int> aux = dfs(it, i);
            aux.first++;
            deep = max(deep, aux);
        }
    }
    return deep;
}

int32_t main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int n, m;
    cin >> n >> m;
    for (int i = 1; i <= m; i++) {
        int a, b;
        cin >> a >> b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    if (m != n - 1) {
        cout << "NO\n";
        return 0;
    }
    if (n == 1) {
        cout << "YES\n1\n1";
        return 0;
    }
    if (n == 2) {
        cout << "YES\n2\n1 1";
        return 0;
    }
    int u = dfs(1).second;
    int v = dfs(u).second;
    for (int i = v; ; i = tata[i]) {
        f[i] = 1;
        viz[i] = 1;
        for (auto c1 : adj[i]) {
            viz[c1] = 1;
            for (auto c2 : adj[c1]) {
                viz[c2] = 1;
            }
        }
        if (i == u) {
            break;
        }
    }
    bool ok = 1;
    for (int i = 1; i <= n; i++) {
        ok = (ok & viz[i]);
    }
    if (!ok) {
        cout << "NO\n";
        return 0;
    }
    vector<int> ans;
    for (int i = tata[v]; i != u; i = tata[i]) {
        ans.push_back(i);
        for (auto it : adj[i]) {
            if (adj[it].size() != 1 && !f[it]) {
                ans.push_back(it);
                ans.push_back(i);
            }
        }
    }
    cout << "YES\n" << ans.size() * 2 + 1 << "\n1 ";
    for (auto it : ans) {
        cout << it << " ";
    }
    reverse(ans.begin(), ans.end());
    for (auto it : ans) {
        cout << it << " ";
    }
    return 0;
}

• Subtask 1: 9 / 12
• Subtask 2: 6 / 8
• Subtask 3: 60 / 80