Submission #1194673

#	Time	Username	Problem	Language	Result	Execution time	Memory
1194673		julia_08	Railway (BOI17_railway)	C++20	7 / 100	29 ms	11196 KiB

railway

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

const int MAXN = 1e5 + 10;

int pre[MAXN], s[MAXN];

vector<int> adj[MAXN];

int t = 0;

void dfs(int v, int p){

  pre[v] = ++t;

  for(auto u : adj[v]){
    if(u != p){
      dfs(u, v);
    }
  }

}

int main(){
  cin.tie(0)->sync_with_stdio(0);

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

  vector<pair<int, int>> edges;

  for(int i=1; i<n; i++){

    int a, b; cin >> a >> b;

    edges.push_back({a, b});

    adj[a].push_back(b);
    adj[b].push_back(a);

  }

  int root = 1;

  for(int i=1; i<=n; i++){
    if(adj[i].size() == 1){
      root = i;
    }
  }

  dfs(root, root);

  while(m--){

    int k; cin >> k;

    int l = n + 1, r = 0;

    for(int i=0; i<k; i++){
      int v; cin >> v;
      l = min(l, pre[v]);
      r = max(r, pre[v]);
    }

    s[l] ++;
    s[r + 1] --;

  }

  for(int i=1; i<=n; i++) s[i] += s[i - 1];

  vector<int> ans;

  for(int i=0; i<(int) edges.size(); i++){
    if(s[pre[edges[i].first]] >= k && s[pre[edges[i].second]] >= k){
      ans.push_back(i + 1);
    }
  }

  cout << (int) ans.size() << "\n";

  for(auto x : ans) cout << x << " ";

  cout << "\n";

  return 0;
}

• Subtask 1: 0 / 8
• Subtask 2: 0 / 15
• Subtask 3: 7 / 7
• Subtask 4: 0 / 29
• Subtask 5: 0 / 16
• Subtask 6: 0 / 25