Submission #922986

#	Time	Username	Problem	Language	Result	Execution time	Memory
922986		Aiperiii	Valley (BOI19_valley)	C++14	0 / 100	501 ms	262144 KiB

valley

#include <bits/stdc++.h>
#define int long long
#define ff first
#define ss second
#define pb push_back
#define all(x) x.begin(),x.end()
using namespace std;
const int N=1e5+5;
vector <int> g[N];
set <int> sbtr[N];
int d[N];
void dfs(int v,int p){
   for(auto to : g[v]){
      if(to!=p){
         d[to]=d[v]+1;
         dfs(to,v);
      }
   }
   sbtr[v].insert(v);
   if(sbtr[p].size()<sbtr[v].size()){
      set <int> st=sbtr[v];
      swap(sbtr[p],sbtr[v]);
      for(auto x : sbtr[v])sbtr[p].insert(x);
      sbtr[v]=st;
   }
   else{
      for(auto x : sbtr[v])sbtr[p].insert(x);
   }
}
signed main(){
   ios_base::sync_with_stdio();
   cin.tie(0);cout.tie(0);
   int n,s,q,e;
   cin>>n>>s>>q>>e;
   vector <int> mag(s),a(n),b(n),c(n);
   for(int i=0;i<n-1;i++){
      cin>>a[i]>>b[i]>>c[i];
      g[a[i]].pb(b[i]);
      g[b[i]].pb(a[i]);
   }
   dfs(e,0);
   for(int i=0;i<s;i++){
      cin>>mag[i];
   }
   while(q--){
      int ind,x;
      cin>>ind>>x;
      ind--;
      int u=a[ind];
      int v=b[ind];
      if(d[u]<d[v])swap(u,v);
      auto it=lower_bound(all(sbtr[u]),x);
      if(it!=sbtr[u].end() && *it==x)cout<<0<<"\n";
      else cout<<"escaped\n";
   }
}

• Subtask 1: 0 / 9
• Subtask 2: 0 / 27
• Subtask 3: 0 / 23
• Subtask 4: 0 / 41