Submission #366373

#	Time	Username	Problem	Language	Result	Execution time	Memory
366373		kshitij_sodani	Planine (COCI21_planine)	C++14	110 / 110	1097 ms	102352 KiB

Main

//#pragma GCC optimize("Ofast,unroll-loops")
#include <bits/stdc++.h>
using namespace std;
typedef long long llo;
#define mp make_pair
#define pb push_back
#define a first 
#define b second
#define endl '\n'


llo n,aa;
llo xx[1000001];
llo yy[1000001];
vector<pair<llo,llo>> ss;
set<pair<llo,llo>> cur;
set<pair<llo,llo>> cur2;
llo ap[1000001];
llo bp[1000001];
bool clock(pair<llo,llo> aa,pair<llo,llo> bb,pair<llo,llo> cc){
	return aa.a*(bb.b-cc.b)+bb.a*(cc.b-aa.b)+cc.a*(aa.b-bb.b)<0;

}
bool clock2(pair<llo,llo> aa,pair<llo,llo> bb,pair<llo,llo> cc){
	return aa.a*(bb.b-cc.b)+bb.a*(cc.b-aa.b)+cc.a*(aa.b-bb.b)<=0;

}
int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cin>>n>>aa;
	for(llo i=0;i<n;i++){
		cin>>xx[i]>>yy[i];
	}

	vector<pair<pair<llo,llo>,llo>> sss;
	for(llo i=1;i<n;i+=2){	
		while(sss.size()>=2){
			if(!clock(sss[sss.size()-2].a,sss.back().a,{xx[i],yy[i]})){
				sss.pop_back();
				continue;
			}
			else{
				break;
			}
		}
		sss.pb({{xx[i],yy[i]},i});
		llo ind=0;
		/*llo low=0;
		llo high=sss.size()-1;*/
		/*while(low<high-1){
			llo mid=(low+high)/2;
			if(clock({xx[i+1],yy[i+1]},sss[ind-(1<<j)+1].a,sss[ind-(1<<j)].a)){
				ind-=(1<<j);
			}
		}*/
		for(llo j=19;j>=0;j--){
			if(ind+(1<<j)<sss.size()){
				if(clock2(sss[ind+(1<<j)-1].a,sss[ind+(1<<j)].a,{xx[i+1],yy[i+1]})){
					ind+=(1<<j);
				}
			}
		}
		ap[i+1]=sss[ind].b;
	}
	sss.clear();
	for(llo i=n-2;i>=0;i-=2){	
		while(sss.size()>=2){
			if(!clock({xx[i],yy[i]},sss.back().a,sss[sss.size()-2].a)){
				sss.pop_back();
				continue;
			}
			else{
				break;
			}
		}
		sss.pb({{xx[i],yy[i]},i});
		llo ind=0;
		/*llo low=0;
		llo high=sss.size()-1;*/
		/*while(low<high-1){
			llo mid=(low+high)/2;
			if(clock({xx[i+1],yy[i+1]},sss[ind-(1<<j)+1].a,sss[ind-(1<<j)].a)){
				ind-=(1<<j);
			}
		}*/
		for(llo j=19;j>=0;j--){
			if(ind+(1<<j)<sss.size()){
				if(!clock({xx[i-1],yy[i-1]},sss[ind+(1<<j)-1].a,sss[ind+(1<<j)].a)){
					ind+=(1<<j);
				}
			}
		}
		bp[i-1]=sss[ind].b;
	}
	//return 0;
	for(llo i=2;i<n-1;i+=2){

	/*	double ac=((double)aa-yy[i]);
		ac/=((double)(yy[i+1]-yy[i]));
		ac*=((double)(xx[i+1]-xx[i]));*/
		pair<llo,llo> acc2={(xx[i+1]-xx[i])*(aa-yy[i]),(yy[i+1]-yy[i])};
		acc2.a+=xx[i]*acc2.b;
		//ac+=xx[i];

		pair<llo,llo> bcc2={(xx[i-1]-xx[i])*(aa-yy[i]),(yy[i-1]-yy[i])};
		bcc2.a+=xx[i]*bcc2.b;
		//ac+=xx[i];
	/*	double bc=((double)aa-yy[i]);
		bc/=((double)(yy[i-1]-yy[i]));
		bc*=((double)(xx[i-1]-xx[i]));*/
		//bc+=xx[i];
		//cout<<setprecision(10)<<ac<<":"<<bc<<endl;
		
		/*ac*=1000000;
		bc*=1000000;
		llo acc=round(ac);
		llo bcc=round(bc);*/
		//if(n<=2000){
			for(llo j=ap[i];j<=ap[i];j+=2){
				//if(j<i){
				if(yy[j]==yy[i]){
					continue;
				}
				pair<llo,llo> ccc2={(xx[j]-xx[i])*(aa-yy[i]),(yy[j]-yy[i])};
				ccc2.a+=xx[i]*ccc2.b;
				if(j<i){
					if(bcc2.a*ccc2.b<ccc2.a*bcc2.b){
						bcc2=ccc2;

					}
				//	bcc=max(bcc,ccc);
				}
				//}
			}
			for(llo j=bp[i];j<=bp[i];j+=2){
				//if(j<i){
				if(yy[j]==yy[i]){
					continue;
				}
				pair<llo,llo> ccc2={(xx[j]-xx[i])*(aa-yy[i]),(yy[j]-yy[i])};
				ccc2.a+=xx[i]*ccc2.b;
					if(j>i){
						if(acc2.a*ccc2.b>ccc2.a*acc2.b){
							acc2=ccc2;

						}
						//acc=min(acc,ccc);
					}
					if(j<i){
						if(bcc2.a*ccc2.b<ccc2.a*bcc2.b){
							bcc2=ccc2;

						}
					//	bcc=max(bcc,ccc);
					}
				//}
			}
		//}
		long double ac=((long double)(acc2.a))/((long double)(acc2.b));
		long double bc=((long double)(bcc2.a))/((long double)(bcc2.b));
		ac*=1000000;
		bc*=1000000;
		llo acc=round(ac);
		llo bcc=round(bc);
		swap(acc,bcc);
		ss.pb({acc,bcc});
		//cout<<acc<<","<<bcc<<endl;

	}
	//return 0;
	for(auto j:ss){
		cur.insert(j);
		cur2.insert({j.b,j.a});
	}
//	sort(ss.begin(),ss.end(),cmp);
	llo ans=0;
	while(cur2.size()){
		ans++;
		pair<llo,llo> no=*(cur2.begin());
	//	cout<<no.a<<":"<<no.b<<endl;
		while(cur.size()){
			pair<llo,llo> no2=*(cur.begin());
		//	cout<<no2.a<<",,"<<no2.b<<endl;
			if(no2.a<=no.a){	
				cur.erase(no2);
				cur2.erase({no2.b,no2.a});
			}
			else{
				break;
			}
		}
		//break;
	}



	cout<<ans<<endl;




 
	return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:58:17: warning: comparison of integer expressions of different signedness: 'llo' {aka 'long long int'} and 'std::vector<std::pair<std::pair<long long int, long long int>, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |    if(ind+(1<<j)<sss.size()){
      |       ~~~~~~~~~~^~~~~~~~~~~
Main.cpp:88:17: warning: comparison of integer expressions of different signedness: 'llo' {aka 'long long int'} and 'std::vector<std::pair<std::pair<long long int, long long int>, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   88 |    if(ind+(1<<j)<sss.size()){
      |       ~~~~~~~~~~^~~~~~~~~~~

• Subtask 1: 20 / 20
• Subtask 2: 30 / 30
• Subtask 3: 60 / 60