Submission #604826

#	Time	Username	Problem	Language	Result	Execution time	Memory
604826		errorgorn	Event Hopping (BOI22_events)	C++17	100 / 100	325 ms	48580 KiB

events

#include <bits/stdc++.h>
using namespace std;

#define int long long
#define ii pair<int,int>
#define fi first
#define se second
#define endl '\n'

#define puf push_front
#define pof pop_front
#define pub push_back
#define pob pop_back
#define lb lower_bound
#define ub upper_bound

#define rep(x,s,e) for (int x=(s)-((s)>(e));x!=(e)-((s)>(e));((s)<(e))?x++:x--)
#define all(x) (x).begin(),(x).end()
#define sz(x) (int) (x).size()

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

struct node{
	int s,e,m;
	ii val=ii(1e9,-1);
	node *l,*r;
	
	node (int _s,int _e){
		s=_s,e=_e,m=s+e>>1;
		
		if (s!=e){
			l=new node(s,m);
			r=new node(m+1,e);
		}
	}
	
	void update(int i,ii k){
		val=min(val,k);
		if (s==e) return;
		if (i<=m) l->update(i,k);
		else r->update(i,k);
	}
	
	ii query(int i,int j){
		if (s==i && e==j) return val;
		else if (j<=m) return l->query(i,j);
		else if (m<i) return r->query(i,j);
		else return min(l->query(i,m),r->query(m+1,j));
	}
} *root=new node(0,200005);

int n,q;
ii range[100005];
int tkd[100005][18];

signed main(){
	cin.tie(0);
	cout.tie(0);
	cin.sync_with_stdio(false);
	
	cin>>n>>q;
	
	rep(x,1,n+1) cin>>range[x].fi>>range[x].se;
	
	vector<int> uni;
	rep(x,1,n+1) uni.pub(range[x].fi),uni.pub(range[x].se);
	sort(all(uni));
	rep(x,1,n+1){
		range[x].fi=lb(all(uni),range[x].fi)-uni.begin();
		range[x].se=lb(all(uni),range[x].se)-uni.begin();
	}
	
	rep(x,1,n+1) root->update(range[x].se,ii(range[x].fi,x));
	
	vector<int> idx;
	rep(x,1,n+1) idx.pub(x);
	
	sort(all(idx),[](int i,int j){
		return range[i].fi<range[j].fi;
	});
	
	memset(tkd,-1,sizeof(tkd));
	for (auto it:idx){
		tkd[it][0]=root->query(range[it].fi,range[it].se).se;
		if (range[tkd[it][0]].fi==range[it].fi) tkd[it][0]=-1;
		int curr=tkd[it][0];
		//cout<<it<<" "<<tkd[it][0]<<endl;
		
		rep(x,0,18){
			if (curr==-1) break;
			curr=tkd[it][x+1]=tkd[curr][x];
		}
	}
	
	int a,b;
	while (q--){
		cin>>a>>b;
		
		if (a==b) cout<<0<<endl;
		else if (range[b].se<range[a].se) cout<<"impossible"<<endl;
		else if (range[b].fi<=range[a].se && range[a].se<=range[b].se) cout<<1<<endl;
		else{
			int ans=0;
			rep(x,18,0) if (tkd[b][x]!=-1 && range[a].se<range[tkd[b][x]].fi){
				b=tkd[b][x];
				ans+=(1<<x);
			}
			
			if (tkd[b][0]!=-1) cout<<ans+2<<endl;
			else cout<<"impossible"<<endl;
		}
	}
}

Compilation message (stderr)

events.cpp: In constructor 'node::node(long long int, long long int)':
events.cpp:29:16: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   29 |   s=_s,e=_e,m=s+e>>1;
      |               ~^~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 15 / 15
• Subtask 4: 15 / 15
• Subtask 5: 20 / 20
• Subtask 6: 30 / 30