Submission #999258

#	Time	Username	Problem	Language	Result	Execution time	Memory
999258		crafticat	Newspapers (CEOI21_newspapers)	C++17	12 / 100	1 ms	500 KiB

newspapers

#include <bits/stdc++.h>

using namespace std;
vector<vector<int>> g;
int MAX_DEP = 0;

vector<int> ans;

void dfs(int x, int p) {
    if (g[x].size() == 1 && p != 0) return;
    ans.push_back(x);
    for (auto child : g[x]) {
        if (child == p) continue;
        dfs(child,x);
    }
    ans.push_back(x);
}

int main() {
    ios_base::sync_with_stdio(false); cin.tie(nullptr);

    int n, m; cin >> n >> m;

    g.resize(n + 1);
    for (int i = 0; i < m; ++i) {
        int a, b; cin >> a >> b;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    if (m != n -1) {
        cout << "NO\n";
        return 0;
    }

    if (n == 1) {
        cout << "YES\n";
        cout << "1\n";
        cout << "1\n";
        return 0;
    }

    vector<int> siz(n + 1);
    for (int i = 1; i <= n; ++i) {
        if (g[i].size() == 1) {
            siz[i]--;
            for (auto child : g[i]) {
                siz[child]--;
            }
        }
        siz[i]+= g[i].size();
    }
    for (int i = 1; i <= n; ++i) {
        if (siz[i] == 1 && g[i].size() <= 3) {
            for (auto child : g[i])
                siz[child]--;
        }
    }
    for (int i = 1; i <= n; ++i) {
        if (siz[i] > 2) {
            cout << "NO\n";
            return 0;
        }
    }
    dfs(1,0);
    cout << "YES\n";
    cout << ans.size() << "\n";
    for (auto x: ans) {
        cout << x << " ";
    }

    return 0;
}

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