Submission #695263

#	Time	Username	Problem	Language	Result	Execution time	Memory
695263		Ahmed_Solyman	Railway (BOI17_railway)	C++14	7 / 100	219 ms	25232 KiB

railway

#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,m,k;
	cin>>n>>m>>k;
	vector<int>adj[n+5];
	vector<int>a(n+5),b(n+5);
	for(int i=0;i<n-1;i++){
		int u,v;cin>>u>>v;
		a[i]=u;b[i]=v;
		adj[u].push_back(v);
		adj[v].push_back(u);
	}
	int root;
	for(int i=1;i<=n;i++){
		if(adj[i].size()==1){
			root=i;
		}
	}
	queue<int>q;
	q.push(root);
	vector<bool>vis(n+5);
	vector<int>c;
	while(q.size()){
		int x=q.front();
		q.pop();
		vis[x]=1;
		c.push_back(x);
		for(auto i:adj[x]){
			if(!vis[i]){
				q.push(i);
			}
		}
	}
	map<int,int>mp;
	for(int i=0;i<n;i++){
		mp[c[i]]=i;
	}
	vector<int>p(n);
	while(m--){
		int k;cin>>k;
		vector<int>v(k);
		for(auto &i:v)cin>>i;
		int l=1e9,r=-1;
		for(auto i:v){
			l=min(l,mp[i]);
			r=max(r,mp[i]);
		}
		p[l]++;
		if(r+1<n){
			p[r+1]--;
		}
	}
	map<pair<int,int>,bool>e;
	for(int i=1;i<n;i++){
		p[i]+=p[i-1];
		if(p[i]>=k && p[i-1]>=k){
			e[{c[i],c[i-1]}]=1;
			e[{c[i-1],c[i]}]=1;
		}
	}
	vector<int>d;
	for(int i=0;i<n-1;i++){
		if(e[{a[i],b[i]}]){
			d.push_back(i+1);
		}
	}
	cout<<d.size()<<endl;
	for(auto i:d)cout<<i<<" ";
}

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