oj.uz

Submission #603308

# Submission time Handle Problem Language Result Execution time Memory
603308 2022-07-24T00:09:23 Z DanerZein Event Hopping (BOI22_events) C++17
20 / 100
 1500 ms 38544 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){
    vector<int> ans(iq);
    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<ans.size();i++){
      if(ans[i]==-1) cout<<"impossible\n";
      else cout<<ans[i]<<endl;
    }
  }
}

Compilation message

events.cpp: In function 'int main()':
events.cpp:139:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  139 |     for(int i=0;i<ans.size();i++){
      |                 ~^~~~~~~~~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 262 ms 30216 KB Output is correct
3 Correct 238 ms 30260 KB Output is correct
4 Correct 301 ms 30208 KB Output is correct
5 Correct 249 ms 29364 KB Output is correct
6 Correct 247 ms 28448 KB Output is correct
7 Correct 293 ms 28212 KB Output is correct
8 Correct 110 ms 22256 KB Output is correct
9 Correct 88 ms 20808 KB Output is correct
10 Correct 175 ms 27428 KB Output is correct
11 Correct 200 ms 25528 KB Output is correct
12 Correct 77 ms 24512 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 448 KB Output is correct
5 Correct 16 ms 448 KB Output is correct
6 Correct 40 ms 1232 KB Output is correct
7 Correct 108 ms 2016 KB Output is correct
8 Correct 144 ms 3076 KB Output is correct
9 Correct 672 ms 4420 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 448 KB Output is correct
5 Correct 16 ms 448 KB Output is correct
6 Correct 40 ms 1232 KB Output is correct
7 Correct 108 ms 2016 KB Output is correct
8 Correct 144 ms 3076 KB Output is correct
9 Correct 672 ms 4420 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 20 ms 448 KB Output is correct
13 Correct 11 ms 448 KB Output is correct
14 Correct 17 ms 448 KB Output is correct
15 Correct 43 ms 1136 KB Output is correct
16 Correct 115 ms 2004 KB Output is correct
17 Correct 132 ms 3068 KB Output is correct
18 Correct 755 ms 4436 KB Output is correct
19 Execution timed out 1548 ms 32824 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 448 KB Output is correct
5 Correct 16 ms 448 KB Output is correct
6 Correct 40 ms 1232 KB Output is correct
7 Correct 108 ms 2016 KB Output is correct
8 Correct 144 ms 3076 KB Output is correct
9 Correct 672 ms 4420 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 19 ms 444 KB Output is correct
13 Correct 12 ms 448 KB Output is correct
14 Correct 16 ms 444 KB Output is correct
15 Correct 39 ms 1216 KB Output is correct
16 Correct 109 ms 2024 KB Output is correct
17 Correct 142 ms 3080 KB Output is correct
18 Correct 706 ms 4436 KB Output is correct
19 Correct 108 ms 29624 KB Output is correct
20 Execution timed out 1579 ms 21452 KB Time limit exceeded
21 Halted 0 ms 0 KB -

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 249 ms 30400 KB Output is correct
2 Correct 240 ms 30268 KB Output is correct
3 Correct 262 ms 30264 KB Output is correct
4 Correct 87 ms 20788 KB Output is correct
5 Correct 174 ms 27432 KB Output is correct
6 Execution timed out 1590 ms 38544 KB Time limit exceeded
7 Halted 0 ms 0 KB -

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 262 ms 30216 KB Output is correct
3 Correct 238 ms 30260 KB Output is correct
4 Correct 301 ms 30208 KB Output is correct
5 Correct 249 ms 29364 KB Output is correct
6 Correct 247 ms 28448 KB Output is correct
7 Correct 293 ms 28212 KB Output is correct
8 Correct 110 ms 22256 KB Output is correct
9 Correct 88 ms 20808 KB Output is correct
10 Correct 175 ms 27428 KB Output is correct
11 Correct 200 ms 25528 KB Output is correct
12 Correct 77 ms 24512 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 448 KB Output is correct
17 Correct 16 ms 448 KB Output is correct
18 Correct 40 ms 1232 KB Output is correct
19 Correct 108 ms 2016 KB Output is correct
20 Correct 144 ms 3076 KB Output is correct
21 Correct 672 ms 4420 KB Output is correct
22 Correct 0 ms 212 KB Output is correct
23 Correct 0 ms 212 KB Output is correct
24 Correct 20 ms 448 KB Output is correct
25 Correct 11 ms 448 KB Output is correct
26 Correct 17 ms 448 KB Output is correct
27 Correct 43 ms 1136 KB Output is correct
28 Correct 115 ms 2004 KB Output is correct
29 Correct 132 ms 3068 KB Output is correct
30 Correct 755 ms 4436 KB Output is correct
31 Execution timed out 1548 ms 32824 KB Time limit exceeded
32 Halted 0 ms 0 KB -