Submission #1322169

#	Time	Username	Problem	Language	Result	Execution time	Memory
1322169		boclobanchat	Mobile (BOI12_mobile)	C++20	100 / 100	316 ms	16076 KiB

mobile

#include<bits/stdc++.h>
using namespace std;
const int MAXN=1e6+5;
long long X[MAXN],Y[MAXN];
double dist(double xa,double ya,double xb,double yb)
{
	return sqrt((xa-xb)*(xa-xb)+(ya-yb)*(ya-yb));
}
double getl(double x,double y,double k)
{
	return x-sqrt(k*k-y*y);
}
double getr(double x,double y,double k)
{
	return x+sqrt(k*k-y*y);
}
int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int n,len;
	cin>>n>>len;
	for(int i=1;i<=n;i++) cin>>X[i]>>Y[i];
	double l=0,r=2e9,ans=2e9;
	while(r-l>1e-7)
	{
		double mid=(l+r)/2,mx=0,mt=0;
		for(int i=1;i<=n;i++) 
		{
			if(abs(Y[i])>mid) continue;
			if(getl(X[i],Y[i],mid)<=mx)
			{
				mx=max(mx,getr(X[i],Y[i],mid));
				mx=max(mx,mt),mt=0;
			}
			else mt=max(mt,getr(X[i],Y[i],mid));
		}
		if(mx>=len) r=ans=mid;
		else l=mid;
	}
	cout<<setprecision(10)<<fixed<<ans;
}

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