Submission #873583

#	Time	Username	Problem	Language	Result	Execution time	Memory
873583		epicci23	Birthday gift (IZhO18_treearray)	C++17	30 / 100	4040 ms	9320 KiB

treearray

#include "bits/stdc++.h"
using namespace std;
#define int long long
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(),(x).end()
#define endl "\n"
#define pb push_back

/*
 dont get stuck on one approach
 write stuff on paper
 edge cases(n=1?)
 look for : dp,bs,bf,observations...
 implement and debug smarter
*/


const int N = 2e5;
const int LOG = 20;

vector<int> v[N];
int lift[N][LOG];
int depth[N];
void dfs(int c,int p,int d){
  depth[c]=d;
  lift[c][0]=p;
  for(int i=1;i<LOG;i++) lift[c][i]=lift[lift[c][i-1]][i-1];
  for(int x:v[c]){
    if(x==p) continue;
    dfs(x,c,d+1);
  }
}

int lca(int a,int b){
  if(depth[a]<depth[b]) swap(a,b);
  int x = depth[a] - depth[b];

  for(int i=0;i<LOG;i++) if(x&(1LL<<i)) a=lift[a][i];
  
  if(a==b) return a;

  for(int i=LOG-1;i>=0;i--){
    if(lift[a][i]!=lift[b][i]){
      a=lift[a][i];
      b=lift[b][i];
    }
  }
  return lift[a][0];
}


void solve(){
  int n,m,q;
  cin >> n >> m >> q;
 
  for(int i=1;i<n;i++){
    int a,b;
    cin >> a >> b;
    v[a].pb(b);
    v[b].pb(a);
  }

  dfs(1,0,0);
  
  int ar[m+5];
  for(int i=1;i<=m;i++) cin >> ar[i];

  while(q--){
    int op;
    cin >> op;

    if(op==1){
      int ind,u;
      cin >> ind >> u;
      ar[ind]=u;
    }
    else{
      int l,r,u;
      cin >> l >> r >> u;
      bool ok=0;
      for(int i=l;i<=r;i++){
        int cur = ar[i];
        if(ok) break;
        for(int j=i;j<=r;j++){
        //  cout << cur << " " << ar[j] << endl;
          cur=lca(cur,ar[j]);
        //  cout << i << " " << j << " lca: " << cur << endl;
          if(cur==u){
            ok=1;
            cout << i << " " << j << endl;
            break;
          }
        }
        if(ok) break;
      } 
      if(ok==0) cout << -1 << " " << -1 << endl;
    }

  }

}

int32_t main(){
  cin.tie(0);
  ios::sync_with_stdio(0);

  int t=1;//cin >> t;
  while(t--) solve();
}

• Subtask 1: 12 / 12
• Subtask 2: 18 / 18
• Subtask 3: 0 / 26
• Subtask 4: 0 / 44