Submission #1140593

#	Time	Username	Problem	Language	Result	Execution time	Memory
1140593		UmairAhmadMirza	Sprinklers (CEOI24_sprinklers)	C++20	100 / 100	145 ms	21384 KiB

Main

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

#define int long long
int const N=2e5+5;
int const mod=1e9+7;

int n,m;
vector<int> flo,spr,rspr;
vector<pair<int,int>> pr;
vector<int> d;

bool solve1(int K){
	deque<int> bh_flo;
	int cur=-(1e9+5);
	// vector<int> d;
	d.clear();
	vector<int> lst;
	reverse(pr.begin(), pr.end());
	int sz=0;
	for(auto [p,t]:pr){
		p*=-1;
		if(t==0){
			sz++;
			while(bh_flo.size()>0 && bh_flo[0]<=cur)
				bh_flo.pop_front();
			if(bh_flo.size()==0){
				d.push_back(1);
				lst.push_back(p);
				cur=p+K;
				continue;
			}
			if(bh_flo[0]<p-K){
				reverse(pr.begin(), pr.end());
				return 0;
			}
			d.push_back(0);
			if(d.size()>2 && rspr[sz-2]>=p-K && rspr[sz-3]>=p-K){
				d[sz-2]=1;
				cur=rspr[sz-2]+K;
				lst.push_back(lst.back());
				while(bh_flo.size()>0 && bh_flo[0]<=cur)
					bh_flo.pop_front();
			}
			else if(d.size()>1 && rspr[sz-2]>=p-K){
				if(lst.back()>=p-K){
					lst.push_back(lst.back());
					d[sz-2]=1;
					cur=rspr[sz-2]+K;
					while(bh_flo.size()>0 && bh_flo[0]<=cur)
						bh_flo.pop_front();
				}
				else
					lst.push_back(bh_flo[0]);
			}
			else
				lst.push_back(bh_flo[0]);
			bh_flo.clear();
		}
		else{
			if(p>cur)
				bh_flo.push_back(p);
		}
	}
	reverse(pr.begin(), pr.end());
	if(bh_flo.size()>0 && bh_flo.back()>cur)
		return 0;
	return 1;
}

bool solve(int K){
	deque<int> bh_flo;
	int cur=-1;
	// vector<int> d;
	d.clear();
	vector<int> lst;
	int sz=0;
	for(auto [p,t]:pr){
		if(t==0){
			sz++;
			while(bh_flo.size()>0 && bh_flo[0]<=cur)
				bh_flo.pop_front();
			if(bh_flo.size()==0){
				d.push_back(1);
				lst.push_back(p);
				cur=p+K;
				continue;
			}
			if(bh_flo[0]<p-K)
				return 0;
			d.push_back(0);
			if(d.size()>2 && spr[sz-2]>=p-K && spr[sz-3]>=p-K){
				d[sz-2]=1;
				cur=spr[sz-2]+K;
				lst.push_back(lst.back());
				while(bh_flo.size()>0 && bh_flo[0]<=cur)
					bh_flo.pop_front();
			}
			else if(d.size()>1 && spr[sz-2]>=p-K){
				if(lst.back()>=p-K){
					lst.push_back(lst.back());
					d[sz-2]=1;
					cur=spr[sz-2]+K;
					while(bh_flo.size()>0 && bh_flo[0]<=cur)
						bh_flo.pop_front();
				}
				else
					lst.push_back(bh_flo[0]);
			}
			else
				lst.push_back(bh_flo[0]);
			bh_flo.clear();
		}
		else{
			if(p>cur)
				bh_flo.push_back(p);
		}
	}
	if(bh_flo.size()>0 && bh_flo.back()>cur)
		return 0;
	return 1;
}

signed main(){
	cin>>n>>m;
	map<int,int> mp;
	for (int i = 0; i < n; ++i)
	{
		int a;
		cin>>a;
		spr.push_back(a);
		rspr.push_back(-a);
		pr.push_back({a,0});
		mp[a]=1;
	}
	for (int i = 0; i < m; ++i)
	{
		int a;
		cin>>a;
		if(mp[a])
			continue;
		flo.push_back(a);
		pr.push_back({a,1});
	}
	// rspr=spr/;
	reverse(rspr.begin(), rspr.end());
	sort(pr.begin(), pr.end());
	int low=-1,high=1e9+1;
	while(high-low>1){
		int mid=(high+low)/2;
		if(solve(mid) || solve1(mid))
			high=mid;
		else
			low=mid;
	}
	if(high==1e9+1)
		cout<<-1<<endl;
	else{
		cout<<high<<endl;
		if(solve1(high)){
			reverse(d.begin(), d.end());
			for(int i:d){
				if(i==1)
					cout<<'L';
				else
					cout<<'R';
			}
			cout<<endl;
			return 0;
		}
		solve(high);
		// cout<<high<<endl;
		for(int i:d){
			if(i==1)
				cout<<'R';
			else
				cout<<'L';
		}
		cout<<endl;
	}
	return 0;
}

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• Subtask 2: 6 / 6
• Subtask 3: 17 / 17
• Subtask 4: 27 / 27
• Subtask 5: 47 / 47