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Submission #603316

# Submission time Handle Problem Language Result Execution time Memory
603316 2022-07-24T00:43:03 Z DanerZein Event Hopping (BOI22_events) C++17
20 / 100
 1500 ms 38632 KB 
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> ii;
typedef pair<ii,int> iii;
typedef vector<ii> vii;
typedef vector<int> vi;
const int MAX_N=1e5+10;
const int MAX=1e9;
vector<vi> G;
vector<vii> que;
vii ev;
int dis[MAX_N];
int ans[MAX_N];
int n;
bool isq[MAX_N];
void bfs(int u){
  for(int i=0;i<n;i++) dis[i]=MAX;
  dis[u]=0; isq[u]=1;
  queue<int> q; q.push(u);
  while(!q.empty()){
    int x=q.front(); q.pop();
    isq[x]=0;
    for(auto &v:G[x]){
      if(dis[v]>dis[x]+1){
	dis[v]=dis[x]+1;
	if(!isq[v]){
	  isq[v]=1;
	  q.push(v);
	}
      }
    }
  }
}
int in[MAX_N];
int pa[MAX_N][32];
int le[MAX_N];
void dfs(int u,int p){
  pa[u][0]=p;
  for(int i=1;i<=20;i++){
    pa[u][i]=pa[pa[u][i-1]][i-1];
  }
  for(auto &v:G[u]){
    if(v!=p) {
      le[v]=le[u]+1;
      dfs(v,u);
    }
  }
}
int father(int u,int v){
  int dif=le[u]-le[v];
  if(dif<0) return -1;
  for(int i=0;i<=20;i++){
    if(dif&(1<<i)) u=pa[u][i];
  }
  if(u!=v) return -1;
  return dif;
}
int con[MAX_N];
int main(){
  ios_base::sync_with_stdio(false);
  cin.tie(NULL); cout.tie(NULL);
  int q; cin>>n>>q;
  bool t2=0;
  if(n<=5000) t2=1;
  vii enp;
  for(int i=0;i<n;i++){
    int a,b; cin>>a>>b;
    ev.push_back(ii(a,b));
    enp.push_back(ii(b,i));
    con[i]=i;
  }
  G.resize(n+1);
  if(t2){
    for(int i=0;i<n;i++){
      for(int j=0;j<n;j++){
	if(ev[j].first<=ev[i].second && ev[i].second<=ev[j].second){
	  G[i].push_back(j);
	}
      }
    }
  }
  else{
    sort(enp.begin(),enp.end());
    for(int i=0;i<n-1;i++){
      if(enp[i].first==enp[i+1].first){
	con[enp[i].second]=enp[i+1].second;
	con[enp[i+1].second]=enp[i].second;
      }
    }
    for(int i=0;i<n;i++){
      auto it=lower_bound(enp.begin(),enp.end(),ii(ev[i].first,0));
      int l=it-enp.begin();
      it=upper_bound(enp.begin(),enp.end(),ii(ev[i].second+1,0));
      int r=it-enp.begin();
      for(int j=l;j<r;j++){
	if(i!=enp[j].second){
	  G[i].push_back(enp[j].second);
	  in[enp[j].second]=1;
	}
      }
    }
    for(int i=0;i<n;i++){
      if(!in[i] || con[i]!=i){
	dfs(i,i);
      }
    }
  }
  int iq=0;
  que.resize(n);
  while(q--){
    int s,e; cin>>s>>e;
    s--; e--;
    if(t2){
      que[s].push_back(ii(e,iq));
      iq++;
    }
    else{
      int ans=father(s,e);
      if(ans!=-1) cout<<ans<<endl;
      else{
	int ca=father(s,con[e])+1;
	if(ca!=0) cout<<ca<<endl;
	else
	  cout<<"impossible\n";
      }
    }
  }
  if(t2){
    for(int i=0;i<n;i++){
      if(que[i].empty()) continue;
      bfs(i);
      for(auto &v:que[i]){
	if(dis[v.first]>=MAX) ans[v.second]=-1;
	else ans[v.second]=dis[v.first];
      }
    }
    for(int i=0;i<iq;i++){
      if(ans[i]==-1) cout<<"impossible\n";
      else cout<<ans[i]<<endl;
    }
  }
}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 247 ms 30272 KB Output is correct
3 Correct 236 ms 30340 KB Output is correct
4 Correct 276 ms 30300 KB Output is correct
5 Correct 244 ms 29384 KB Output is correct
6 Correct 231 ms 28596 KB Output is correct
7 Correct 261 ms 28316 KB Output is correct
8 Correct 124 ms 22204 KB Output is correct
9 Correct 88 ms 20732 KB Output is correct
10 Correct 188 ms 27520 KB Output is correct
11 Correct 207 ms 25560 KB Output is correct
12 Correct 81 ms 24508 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 5 ms 340 KB Output is correct
4 Correct 6 ms 340 KB Output is correct
5 Correct 6 ms 408 KB Output is correct
6 Correct 11 ms 1108 KB Output is correct
7 Correct 19 ms 2044 KB Output is correct
8 Correct 19 ms 3072 KB Output is correct
9 Correct 9 ms 4424 KB Output is correct

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 5 ms 340 KB Output is correct
4 Correct 6 ms 340 KB Output is correct
5 Correct 6 ms 408 KB Output is correct
6 Correct 11 ms 1108 KB Output is correct
7 Correct 19 ms 2044 KB Output is correct
8 Correct 19 ms 3072 KB Output is correct
9 Correct 9 ms 4424 KB Output is correct
10 Correct 1 ms 340 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 5 ms 340 KB Output is correct
13 Correct 5 ms 340 KB Output is correct
14 Correct 6 ms 396 KB Output is correct
15 Correct 10 ms 1108 KB Output is correct
16 Correct 17 ms 2040 KB Output is correct
17 Correct 20 ms 3048 KB Output is correct
18 Correct 9 ms 4436 KB Output is correct
19 Execution timed out 1575 ms 31912 KB Time limit exceeded
20 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 5 ms 340 KB Output is correct
4 Correct 6 ms 340 KB Output is correct
5 Correct 6 ms 408 KB Output is correct
6 Correct 11 ms 1108 KB Output is correct
7 Correct 19 ms 2044 KB Output is correct
8 Correct 19 ms 3072 KB Output is correct
9 Correct 9 ms 4424 KB Output is correct
10 Correct 0 ms 340 KB Output is correct
11 Correct 0 ms 340 KB Output is correct
12 Correct 5 ms 340 KB Output is correct
13 Correct 6 ms 568 KB Output is correct
14 Correct 6 ms 440 KB Output is correct
15 Correct 9 ms 1108 KB Output is correct
16 Correct 24 ms 2004 KB Output is correct
17 Correct 22 ms 3096 KB Output is correct
18 Correct 8 ms 4436 KB Output is correct
19 Correct 114 ms 29692 KB Output is correct
20 Execution timed out 1593 ms 21508 KB Time limit exceeded
21 Halted 0 ms 0 KB -

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 237 ms 30200 KB Output is correct
2 Correct 239 ms 30284 KB Output is correct
3 Correct 264 ms 30368 KB Output is correct
4 Correct 88 ms 20792 KB Output is correct
5 Correct 177 ms 27516 KB Output is correct
6 Execution timed out 1584 ms 38632 KB Time limit exceeded
7 Halted 0 ms 0 KB -

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 247 ms 30272 KB Output is correct
3 Correct 236 ms 30340 KB Output is correct
4 Correct 276 ms 30300 KB Output is correct
5 Correct 244 ms 29384 KB Output is correct
6 Correct 231 ms 28596 KB Output is correct
7 Correct 261 ms 28316 KB Output is correct
8 Correct 124 ms 22204 KB Output is correct
9 Correct 88 ms 20732 KB Output is correct
10 Correct 188 ms 27520 KB Output is correct
11 Correct 207 ms 25560 KB Output is correct
12 Correct 81 ms 24508 KB Output is correct
13 Correct 0 ms 340 KB Output is correct
14 Correct 0 ms 212 KB Output is correct
15 Correct 5 ms 340 KB Output is correct
16 Correct 6 ms 340 KB Output is correct
17 Correct 6 ms 408 KB Output is correct
18 Correct 11 ms 1108 KB Output is correct
19 Correct 19 ms 2044 KB Output is correct
20 Correct 19 ms 3072 KB Output is correct
21 Correct 9 ms 4424 KB Output is correct
22 Correct 1 ms 340 KB Output is correct
23 Correct 0 ms 212 KB Output is correct
24 Correct 5 ms 340 KB Output is correct
25 Correct 5 ms 340 KB Output is correct
26 Correct 6 ms 396 KB Output is correct
27 Correct 10 ms 1108 KB Output is correct
28 Correct 17 ms 2040 KB Output is correct
29 Correct 20 ms 3048 KB Output is correct
30 Correct 9 ms 4436 KB Output is correct
31 Execution timed out 1575 ms 31912 KB Time limit exceeded
32 Halted 0 ms 0 KB -