Submission #919363

#	Time	Username	Problem	Language	Result	Execution time	Memory
919363		ethanv13	Mobile (BOI12_mobile)	C++17	0 / 100	1052 ms	94988 KiB

mobile

#include <bits/stdc++.h>
using namespace std;
vector<pair<long long,long long>>c;long long n,l;
bool can(long double mid){
	set<pair<long double,long double>>seg;
	for(int i=0;i<n;++i){
		if(mid<abs(c[i].second)){
			return false;
		}
		else {
			long double delta=sqrt(mid*mid-c[i].second*c[i].second);
			seg.insert({c[i].first-delta,c[i].first+delta});
		}
	}
	long double minx=4e9;
	long double currub=-4e9;
	for(set<pair<long double,long double>>::iterator k=seg.begin();k!=seg.end();++k){
		pair<long double,long double> p=*k;
		if(minx>p.first){
			minx=p.first;
		}
		if(p.first<=currub||currub==-4e9){
			currub=p.second;continue;
		}
		else {
			return false;
		}
	}
	return currub>=l&&minx<=0;
}
int main() {
	cin>>n>>l;
	for(int i=0;i<n;++i){
		long long x,y;cin>>x>>y;c.push_back({x,y});
	}
	long double lo=0;long double hi=2e9;
	for(int i=0;i<50;++i){
		long double mid=(lo+hi)/2;
		if(can(mid)){
			hi=mid;
		}
		else {
			lo=mid;
		}
	}
	cout<<fixed<<setprecision(9);
	cout<<lo<<endl;
};

• Subtask 1: 0 / 4
• Subtask 2: 0 / 4
• Subtask 3: 0 / 4
• Subtask 4: 0 / 4
• Subtask 5: 0 / 4
• Subtask 6: 0 / 5
• Subtask 7: 0 / 5
• Subtask 8: 0 / 5
• Subtask 9: 0 / 5
• Subtask 10: 0 / 5
• Subtask 11: 0 / 5
• Subtask 12: 0 / 5
• Subtask 13: 0 / 5
• Subtask 14: 0 / 5
• Subtask 15: 0 / 5
• Subtask 16: 0 / 5
• Subtask 17: 0 / 5
• Subtask 18: 0 / 5
• Subtask 19: 0 / 5
• Subtask 20: 0 / 5
• Subtask 21: 0 / 5