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Submission #603311

# Submission time Handle Problem Language Result Execution time Memory
603311 2022-07-24T00:11:59 Z DanerZein Event Hopping (BOI22_events) C++14
20 / 100
 1500 ms 38320 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 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){
    int ans[iq+1];
    for(int i=0;i<n;i++){
      bfs(i);
      for(auto &v:que[i]){
	int s=i; int e=v.first;
	bfs(s);
	if(dis[e]>=MAX) ans[v.second]=-1;
	else ans[v.second]=dis[e];
      }
    }
    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 212 KB Output is correct
2 Correct 266 ms 30244 KB Output is correct
3 Correct 249 ms 30252 KB Output is correct
4 Correct 272 ms 30228 KB Output is correct
5 Correct 262 ms 29328 KB Output is correct
6 Correct 233 ms 28472 KB Output is correct
7 Correct 309 ms 28336 KB Output is correct
8 Correct 138 ms 22268 KB Output is correct
9 Correct 86 ms 20732 KB Output is correct
10 Correct 189 ms 27616 KB Output is correct
11 Correct 175 ms 25544 KB Output is correct
12 Correct 77 ms 24464 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 18 ms 452 KB Output is correct
4 Correct 11 ms 340 KB Output is correct
5 Correct 16 ms 340 KB Output is correct
6 Correct 49 ms 1228 KB Output is correct
7 Correct 119 ms 2020 KB Output is correct
8 Correct 136 ms 3080 KB Output is correct
9 Correct 688 ms 4436 KB Output is correct

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 18 ms 452 KB Output is correct
4 Correct 11 ms 340 KB Output is correct
5 Correct 16 ms 340 KB Output is correct
6 Correct 49 ms 1228 KB Output is correct
7 Correct 119 ms 2020 KB Output is correct
8 Correct 136 ms 3080 KB Output is correct
9 Correct 688 ms 4436 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 17 ms 340 KB Output is correct
13 Correct 10 ms 340 KB Output is correct
14 Correct 16 ms 448 KB Output is correct
15 Correct 40 ms 1108 KB Output is correct
16 Correct 120 ms 2020 KB Output is correct
17 Correct 135 ms 3076 KB Output is correct
18 Correct 706 ms 4436 KB Output is correct
19 Execution timed out 1591 ms 31932 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 212 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 18 ms 452 KB Output is correct
4 Correct 11 ms 340 KB Output is correct
5 Correct 16 ms 340 KB Output is correct
6 Correct 49 ms 1228 KB Output is correct
7 Correct 119 ms 2020 KB Output is correct
8 Correct 136 ms 3080 KB Output is correct
9 Correct 688 ms 4436 KB Output is correct
10 Correct 0 ms 340 KB Output is correct
11 Correct 0 ms 224 KB Output is correct
12 Correct 19 ms 468 KB Output is correct
13 Correct 11 ms 444 KB Output is correct
14 Correct 17 ms 448 KB Output is correct
15 Correct 41 ms 1108 KB Output is correct
16 Correct 109 ms 2024 KB Output is correct
17 Correct 137 ms 3068 KB Output is correct
18 Correct 714 ms 4436 KB Output is correct
19 Correct 121 ms 29584 KB Output is correct
20 Execution timed out 1584 ms 21208 KB Time limit exceeded
21 Halted 0 ms 0 KB -

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 235 ms 30260 KB Output is correct
2 Correct 244 ms 30260 KB Output is correct
3 Correct 290 ms 30188 KB Output is correct
4 Correct 86 ms 20736 KB Output is correct
5 Correct 185 ms 27400 KB Output is correct
6 Execution timed out 1584 ms 38320 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 212 KB Output is correct
2 Correct 266 ms 30244 KB Output is correct
3 Correct 249 ms 30252 KB Output is correct
4 Correct 272 ms 30228 KB Output is correct
5 Correct 262 ms 29328 KB Output is correct
6 Correct 233 ms 28472 KB Output is correct
7 Correct 309 ms 28336 KB Output is correct
8 Correct 138 ms 22268 KB Output is correct
9 Correct 86 ms 20732 KB Output is correct
10 Correct 189 ms 27616 KB Output is correct
11 Correct 175 ms 25544 KB Output is correct
12 Correct 77 ms 24464 KB Output is correct
13 Correct 0 ms 212 KB Output is correct
14 Correct 0 ms 340 KB Output is correct
15 Correct 18 ms 452 KB Output is correct
16 Correct 11 ms 340 KB Output is correct
17 Correct 16 ms 340 KB Output is correct
18 Correct 49 ms 1228 KB Output is correct
19 Correct 119 ms 2020 KB Output is correct
20 Correct 136 ms 3080 KB Output is correct
21 Correct 688 ms 4436 KB Output is correct
22 Correct 0 ms 212 KB Output is correct
23 Correct 0 ms 212 KB Output is correct
24 Correct 17 ms 340 KB Output is correct
25 Correct 10 ms 340 KB Output is correct
26 Correct 16 ms 448 KB Output is correct
27 Correct 40 ms 1108 KB Output is correct
28 Correct 120 ms 2020 KB Output is correct
29 Correct 135 ms 3076 KB Output is correct
30 Correct 706 ms 4436 KB Output is correct
31 Execution timed out 1591 ms 31932 KB Time limit exceeded
32 Halted 0 ms 0 KB -