제출 #1228609

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1228609		_rain_	Event Hopping (BOI22_events)	C++20	30 / 100	1595 ms	12480 KiB

events

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

const int N=(int)1e5;
const int INF=(int)1e9;
	int s[N+2],e[N+2],l[N+2],r[N+2];
	int n,q,limit_size;
	vector<int>pp;
	vector<int>nen;

class Segment_tree{
	public:
		vector<int>st;
		void init(int _n){
			st.assign(_n*4+2,INF);
			return;
		}
		void upd(int id,int l,int r,int pos,int val){
			if (l>pos||r<pos) return;
			if (l==r) st[id]=min(st[id],val);
			else {
				int m=(l+r)/2;
				upd(id*2,l,m,pos,val);
				upd(id*2+1,m+1,r,pos,val);
				st[id]=min(st[id*2],st[id*2+1]);
			}
			return;
		}
		int Get(int id,int l,int r,int u,int v){
			if (l>v||r<u) return INF;
			if (u<=l&&r<=v) return st[id];
			int m=(l+r)/2;
			return min(Get(id*2,l,m,u,v),Get(id*2+1,m+1,r,u,v));
		}
};
Segment_tree st;


int Find(int x){
	return upper_bound(nen.begin(),nen.end(),x)-nen.begin();
}

namespace subtask1{
	bool check(){
		return n<=5000;
	}
	
	const int LIMIT_SIZE=3000;
	
	int f[LIMIT_SIZE+2][LIMIT_SIZE+2];
	
	void process(int x){
		st.init(limit_size);
		st.upd(1,1,limit_size,e[x],0);
		f[x][x]=0;
		for(auto&id:pp){
			int val=st.Get(1,1,limit_size,s[id],e[id])+1;
			st.upd(1,1,limit_size,e[id],val);
			if (id==x) continue;
			f[x][id]=val;
		}
		return;
	}
	
	void main_code(){
		for(int i=1;i<=n;++i) process(i);
		for(int i=1;i<=q;++i) {
			int val=f[l[i]][r[i]];
			if (val>=INF) cout<<"impossible\n";
				else cout<<val<<'\n';
		}
		return;
	}
}

namespace subtask2{
	bool check(){
		return q<=1000;
	}

		
	int process(int x,int target){
		if (x==target) return 0;
		st.init(limit_size);
		st.upd(1,1,limit_size,e[x],0);
		for(auto&id:pp){
			int val=st.Get(1,1,limit_size,s[id],e[id])+1;
			st.upd(1,1,limit_size,e[id],val);
			if (id==target) return val;
		}
		return INF;
	}
	
	void main_code(){
		for(int i=1;i<=q;++i) {
			int k=process(l[i],r[i]);
			if (k>=INF) cout<<"impossible\n";
				else cout<<k<<'\n';
		}
		return;
	}
}

namespace subtask3{
	bool check(){
		return true;
	}
	
	const int MAXLOG=(int)17;
		int par[N+2][MAXLOG+2];
		int id[N+2];
	
		int binary_jump(int x,int target){
			if (id[x]>id[target]) return INF;
			if (id[target]==id[x]) return 0;
			x=id[x];
			int ans=0;
			for(int i=MAXLOG;i>=0;--i){
				if (par[x][i]<id[target]){
					ans+=(1<<i);
					x=par[x][i];
				}
			}
			for(int i=0;i<=MAXLOG;++i){
				if (par[x][i]>=id[target]){
					return ans+(1<<i);
				}
			}
			return INF;
		}
	
	void main_code(){
		
		
		for(int i=0,j=0;i<pp.size();++i){
			while (j<pp.size() && s[pp[j]]<=e[pp[i]] && e[pp[i]]<=e[pp[j]]) ++j;
			par[i][0]=j-1;
			id[pp[i]]=i;
		}
		for(int j=1;j<=MAXLOG;++j){
			for(int i=0;i<n;++i){
				par[i][j]=par[par[i][j-1]][j-1];
			}	
		}
		

		
		for(int i=1;i<=q;++i){
			int k=binary_jump(l[i],r[i]);
			if (k>=INF) cout<<"impossible\n";
				else cout<<k<<'\n';
		}
		return;
	}
}

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0) ; cout.tie(0);
	#define task "main"
	if (fopen(task".inp","r")){
		freopen(task".inp","r",stdin);
		freopen(task".out","w",stdout);
	}
	
	cin>>n>>q;
	for(int i=1;i<=n;++i) cin>>s[i]>>e[i];
	for(int i=1;i<=q;++i) cin>>l[i]>>r[i];
	
	for(int i=1;i<=n;++i) {
		nen.push_back(s[i]);
		nen.push_back(e[i]);
	}
	sort(nen.begin(),nen.end());
	nen.resize(unique(nen.begin(),nen.end())-nen.begin());
	limit_size=nen.size();
	for(int i=1;i<=n;++i){
		s[i]=Find(s[i]) , e[i]=Find(e[i]);
		pp.push_back(i);
	}
	sort(pp.begin(),pp.end(),[&](int x,int y){
		if (s[x]!=s[y]) return s[x]<s[y];
		return e[x]<e[y];
	});
	if (subtask2::check()) return subtask2::main_code(),0;
//	if (subtask1::check()) return subtask1::main_code(),0;
	if (subtask3::check()) return subtask3::main_code(),0;
	return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

events.cpp: In function 'int main()':
events.cpp:163:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  163 |                 freopen(task".inp","r",stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
events.cpp:164:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  164 |                 freopen(task".out","w",stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 10 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 15
• Subtask 5: 20 / 20
• Subtask 6: 0 / 30