oj.uz

Submission #858830

# Submission time Handle Problem Language Result Execution time Memory
858830 2023-10-09T08:47:36 Z danikoynov Newspapers (CEOI21_newspapers) C++14
6 / 100
 12 ms 604 KB 
/**
 ____ ____ ____ ____ ____ ____
||l |||e |||i |||n |||a |||d ||
||__|||__|||__|||__|||__|||__||
|/__\|/__\|/__\|/__\|/__\|/__\|

**/

#include<bits/stdc++.h>
#define endl '\n'

using namespace std;
typedef long long ll;

void speed()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
}

const int maxn = 1010;
int n, m;
vector < int > adj[maxn];

int used[maxn], rev[maxn];
void bfs(int v)
{
    for (int i = 1; i <= n; i ++)
        used[i] = -1;
    used[v] = 0;
    rev[v] = 0;
    queue < int > q;
    q.push(v);
    while(!q.empty())
    {
        int cur = q.front();
        q.pop();
        for (int u : adj[cur])
        {
            if (used[u] == -1)
            {
                used[u] = used[cur] + 1;
                rev[u] = cur;
                q.push(u);
            }
        }
    }
}

vector < pair < int, int > > acc[maxn];

    vector < int > seq;
vector < int > act;

int mark[maxn];
void add_to_seq(int ver)
{
    seq.push_back(ver);
    int i = 0;
    while(i < act.size() && act[i] != ver)
        i ++;
    if (i != act.size())
        act.erase(act.begin() + i);

    for (int i = 1; i <= n; i ++)
    {
        mark[i] = 0;
    }
    vector < int > new_act;
    for (int v : act)
    {
        for (int u : adj[v])
            mark[u] = 1;
    }


    for (int i = 1; i <= n; i ++)
        if (mark[i])
        new_act.push_back(i);

    act = new_act;
}

int get_dfs(int v, int p)
{
    if (mark[v])
        return v;
    for (int u : adj[v])
    {
        if (u == p)
            continue;
        int tr = get_dfs(u, v);
        if (tr != -1)
            return tr;
    }
    return -1;
}
void solve()
{
    cin >> n >> m;
    if (m != n - 1)
    {
        cout << "NO" << endl;
        return;
    }
    for (int i = 1; i <= m; i ++)
    {
        int v, u;
        cin >> v >> u;
        adj[v].push_back(u);
        adj[u].push_back(v);
    }

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

    if (n == 2)
    {
        cout << "YES" << endl << 2 << endl << "1 1" << endl;
        return;
    }

    bfs(1);
    int s = 1;
    for (int i = 1; i <= n; i ++)
        if (used[i] > used[s])
        s = i;

    bfs(s);
    int t = 1;
    for (int i = 1; i <= n; i ++)
        if (used[i] > used[t])
            t = i;
        /**for (int i = 1; i <= n; i ++)
            cout << used[i] << " ";
        cout << endl;*/

    vector < int > chain;
    int ver = t;
    while(ver != s)
    {
        chain.push_back(ver);
        ver = rev[ver];
    }
    chain.push_back(ver);
    reverse(chain.begin(), chain.end());

    /**cout << "-----------" << endl;
    for (int cur : chain)
        cout << cur << " ";
    cout << endl;*/
    for (int i = 1; i <= n; i ++)
    {
        used[i] = 0;
    }

    chain.erase(chain.begin());
    chain.pop_back();

    for (int cur : chain)
    {
        used[cur] = 1;
    }

    for (int cur : chain)
    {
        for (int nb : adj[cur])
        {
            if (used[nb])
                continue;
            for (int u : adj[nb])
            {
                if (u != cur)
                {
                    acc[cur].push_back({nb, u});
                }
            }
        }
    }

    /**for (int cur : chain)
        cout << cur << " ";
    cout << endl;*/
    for (int i = 1; i <= n; i ++)
    act.push_back(i);

    for (int cur : chain)
    {
        add_to_seq(cur);
        for (pair < int, int > d : acc[cur])
        {
                   add_to_seq(d.first);
                   add_to_seq(cur);
        }
    }

    /**for (int cur : act)
        cout << cur << " ";
    cout << endl;*/

    int cnt = 0;
    while(act.size() > 0)
    {
        for (int i = 1; i <= n; i ++)
            mark[i] = 0;
        for (int cur : act)
            mark[cur] = 1;

        cnt ++;
        assert(cnt < 10 * n);
        int ver = get_dfs(s, -1);
        add_to_seq(ver);
    }

    cout << "YES" << endl;
    cout << seq.size() << endl;
    for (int cur : seq)
        cout << cur << " ";
    cout << endl;



}

int main()
{
    solve();
    return 0;
}
/**
7 6
1 2
2 3
1 4
4 5
1 6
6 7

*/

Compilation message

newspapers.cpp: In function 'void add_to_seq(int)':
newspapers.cpp:61:13: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   61 |     while(i < act.size() && act[i] != ver)
      |           ~~^~~~~~~~~~~~
newspapers.cpp:63:11: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   63 |     if (i != act.size())
      |         ~~^~~~~~~~~~~~~

Subtask #1
0.0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Partially correct 0 ms 348 KB Provide a successful but not optimal strategy.
5 Correct 1 ms 500 KB Output is correct
6 Partially correct 0 ms 348 KB Provide a successful but not optimal strategy.
7 Correct 0 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Runtime error 1 ms 604 KB Execution killed with signal 6
10 Halted 0 ms 0 KB -

Subtask #2
6.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 1 ms 600 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Partially correct 0 ms 348 KB Provide a successful but not optimal strategy.
5 Correct 0 ms 348 KB Output is correct
6 Partially correct 0 ms 344 KB Provide a successful but not optimal strategy.
7 Correct 0 ms 348 KB Output is correct
8 Partially correct 0 ms 348 KB Provide a successful but not optimal strategy.
9 Correct 0 ms 348 KB Output is correct
10 Partially correct 0 ms 348 KB Provide a successful but not optimal strategy.
11 Partially correct 11 ms 344 KB Provide a successful but not optimal strategy.
12 Correct 3 ms 348 KB Output is correct
13 Partially correct 5 ms 348 KB Provide a successful but not optimal strategy.
14 Partially correct 5 ms 528 KB Provide a successful but not optimal strategy.
15 Correct 6 ms 348 KB Output is correct
16 Partially correct 11 ms 348 KB Provide a successful but not optimal strategy.
17 Correct 11 ms 344 KB Output is correct
18 Partially correct 11 ms 568 KB Provide a successful but not optimal strategy.
19 Correct 12 ms 348 KB Output is correct
20 Partially correct 11 ms 344 KB Provide a successful but not optimal strategy.

Subtask #3
0.0 / 80.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Partially correct 0 ms 348 KB Provide a successful but not optimal strategy.
5 Correct 1 ms 500 KB Output is correct
6 Partially correct 0 ms 348 KB Provide a successful but not optimal strategy.
7 Correct 0 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Runtime error 1 ms 604 KB Execution killed with signal 6
10 Halted 0 ms 0 KB -