Submission #1067441

#	Time	Username	Problem	Language	Result	Execution time	Memory
1067441		Andrey	Newspapers (CEOI21_newspapers)	C++14	0 / 100	1 ms	860 KiB

newspapers

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

vector<int> haha[10000];
int n,m;

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    cin >> n >> m;
    int a,b;
    for(int i = 0; i < m; i++) {
        cin >> a >> b;
        haha[a].push_back(b);
        haha[b].push_back(a);
    }
    if(m > n-1) {
        cout << "NO" << endl;
        return 0;
    }
    vector<int> br(n+1);
    for(int i = 1; i <= n; i++) {
        br[i] = haha[i].size();
    }
    for(int i = 1; i <= n; i++) {
        if(haha[i].size() == 1) {
            br[haha[i][0]]--;
            br[i] = -1;
        }
    }
    vector<int> br1(n+1);
    for(int i = 1; i <= n; i++) {
        br1[i] = br[i];
    }
    bool yeah = false;
    for(int i = 1; i <= n; i++) {
        if(br1[i] <= 1 && br1[i] >= 0) {
            for(int v: haha[i]) {
                br[v]--;
            }
            br[i] = -1;
        }
    }
    for(int i = 1; i <= n; i++) {
        if(br[i] > 2) {
            yeah = true;
        }
    }
    if(yeah) {
        cout << "NO\n";
    }
    else {
        cout << "YES\n";
        if(n == 1) {
            cout << 1 << endl << 1 << endl;
            return 0;
        }
        int y = -1;
        for(int i = 1; i <= n; i++) {
            if(br[i] >= 0) {
                y = i;
            }
        }
        if(y == -1) {
            cout << 2 << endl;
            for(int i = 1; i <= n; i++) {
                if(br1[i] >= 0) {
                    cout << i << " " << i << endl;
                    return 0;
                }
            }
        }
        vector<int> wow(0);
        while(true) {
            wow.push_back(y);
            bool yeah = false;
            for(int v: haha[y]) {
                if(br[v] >= 1 && (wow.size() == 1 || wow[wow.size()-2] != v)) {
                    y = v;
                    yeah = true;
                    break;
                }
            }
            if(!yeah) {
                break;
            }
        }
        vector<int> ans(0);
        for(int i = 0; i < wow.size(); i++) {
            int a = wow[i];
            if(i > 0) {
                ans.push_back(a);
            }
            for(int v: haha[a]) {
                if(br1[v] == 1) {
                    ans.push_back(v);
                    ans.push_back(a);
                }
            }
        }
        ans.pop_back();
        cout << ans.size()*2 << endl;
        for(int i = 0; i < ans.size(); i++) {
            cout << ans[i] << " ";
        }
        if(ans.size()%2) {
            for(int i = 0; i < ans.size(); i++) {
                cout << ans[i] << " ";
            }
        }
        else {
            for(int i = ans.size()-1; i >= 0; i--) {
                cout << ans[i] << " ";
            }
        }
        cout << endl;
    }
    return 0;
}

Compilation message (stderr)

newspapers.cpp: In function 'int main()':
newspapers.cpp:91:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   91 |         for(int i = 0; i < wow.size(); i++) {
      |                        ~~^~~~~~~~~~~~
newspapers.cpp:105:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  105 |         for(int i = 0; i < ans.size(); i++) {
      |                        ~~^~~~~~~~~~~~
newspapers.cpp:109:30: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  109 |             for(int i = 0; i < ans.size(); i++) {
      |                            ~~^~~~~~~~~~~~

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