Submission #1115358

#	Time	Username	Problem	Language	Result	Execution time	Memory
1115358		0pt1mus23	Pastiri (COI20_pastiri)	C++14	100 / 100	452 ms	81828 KiB

pastiri

#pragma GCC optimize("Ofast,unroll-loops")

// el psy congroo
#include <bits/stdc++.h>
using namespace std;
#define int long long int
#define ins insert      
#define pii pair<int,int>
#define pb push_back
#define endl '\n'
#define putr(x) cout<<x<<endl;return; 
#define all(x) x.begin(),x.end()
const int mod = 998244353, sze = 5e5+23, inf = LLONG_MAX, LG = 17;
vector<int> graph[sze];
int used[sze];
int dist[sze];
int d[sze];
int hig[sze];

void dfs(int node,int par=0,int mx=-23,int best=1){
    if( (d[node] + dist[node] )> mx ){
        mx=d[node]+dist[node];
        best=node;
    }
    hig[node]=best;
    for(auto v:graph[node]){
        if(v!=par){
            d[v]=d[node]+1;
            dfs(v,node,mx,best);
        }
    }
}
void sil(int node,int par=0){
    used[node]=1;
    for(auto v:graph[node]){
        if(!used[v] && dist[node]==dist[v]+1){
            sil(v,node);
        }
    }
}
void fast(){
    int n,k;
    cin>>n>>k;
    for(int i =1;i<n;i++){
        int u,v;
        cin>>u>>v;
        graph[u].pb(v);
        graph[v].pb(u);
    }
    for(int i =1;i<=n;i++){
        dist[i]=inf;
    }

    queue<int> q;

    vector<int> sheep(k);
    for(auto &v:sheep){
        cin>>v;
        q.push(v);
        dist[v]=0;
    }

    while(!q.empty()){
        int node = q.front();q.pop();
        for(auto v:graph[node]){
            if(dist[v] > dist[node]+1){
                dist[v]=dist[node]+1;
                q.push(v);
            }
        }
    }
    dfs(1);
    sort(all(sheep),[&](int a,int b){
        return d[a]>d[b];
    });
    vector<int> ans;
    for(auto v:sheep){
        if(!used[v]){
            sil(hig[v]);
            ans.pb(hig[v]);
        }
    }

    cout<<ans.size()<<"\n";
    for(auto v:ans) cout<<v<<" ";cout<<endl;


}
 
signed main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
 
    int tt = 1;
    // cin>>tt;
 
    while(tt--){
        fast();
    }
    return 0;
}

Compilation message (stderr)

pastiri.cpp: In function 'void fast()':
pastiri.cpp:85:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   85 |     for(auto v:ans) cout<<v<<" ";cout<<endl;
      |     ^~~
pastiri.cpp:85:34: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   85 |     for(auto v:ans) cout<<v<<" ";cout<<endl;
      |                                  ^~~~

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