Submission #1004222

#	Time	Username	Problem	Language	Result	Execution time	Memory
1004222		vjudge1	Pastiri (COI20_pastiri)	C++17	0 / 100	503 ms	66232 KiB

pastiri

#include<bits/stdc++.h>

using namespace std;

const int N = 5e5+5;
int n, k, dist[N], in[N];
vector<int> s, G[N], P[N], ans;
bool p[N], seen[N];

void bfs()
{
  queue<int> Q;
  for(int i = 1; i <= n; i ++) dist[i] = N + 20;
  for(int i : s)
    dist[i] = 0, Q.push(i), p[i] = true;

  while(Q.size())
    {
      int u = Q.front();
      Q.pop();
      for(int  v: G[u])
	if(dist[u] + 1 <= dist[v])
	  {
	    P[v].push_back(u);
	    in[u]++;
	    	    
	    if(dist[v] > dist[u] + 1)
	      {
		dist[v] = dist[u] + 1;
		Q.push(v);
	      }
	  }
    }
}

void solve()
{
  queue<int> Q;
  for(int i = 1; i <= n; i ++)
    if(in[i] == 0)
      Q.push(i);

  while(Q.size())
    {
      int u = Q.front();
      Q.pop();
      if(P[u].size() == 1)
	{
	  in[P[u][0]]--;
	  if(in[P[u][0]] == 0)
	    Q.push(P[u][0]);
	}
      else
	ans.push_back(u);
    }
}

int main()
{
  cin >> n >> k;

  for(int i = 1; i < n; i ++)
    {
      int u, v;
      cin >> u >> v;
      G[u].push_back(v);
      G[v].push_back(u);
    }
  
  s.resize(k);
  for(int i = 0; i < k; i ++)
    cin >> s[i];

  bfs();
  solve();
  
  cout << ans.size() << endl;
  for(int v : ans) cout << v << ' ';
  cout << endl;
  
  return 0;
}

• Subtask 1: 0 / 8
• Subtask 2: 0 / 18
• Subtask 3: 0 / 23
• Subtask 4: 0 / 51