제출 #1310460

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1310460		artoria_hermes	Mobile (BOI12_mobile)	C++20	100 / 100	490 ms	8260 KiB

mobile

#include<bits/stdc++.h>
using namespace std;
#define endl "\n"

int n,l;
pair<int,int> a[1000005];
const double eps = 1e-7;

bool check(double mx)
{
  double lim=0.0;
  for (int i=1; i<=n; i++)
  {
    double lower_pos = double(a[i].first) - sqrt(mx*mx - double(a[i].second)*double(a[i].second));
    double upper_pos = double(a[i].first) + sqrt(mx*mx - double(a[i].second)*double(a[i].second));
    if (lower_pos <= lim) lim=max(lim, upper_pos);
  }
  return (lim >= l);
}

signed main()
{
  ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
	cin >> n >> l;
  for (int i=1; i<=n; i++) cin >> a[i].first >> a[i].second;
  double l=0, r=4*1e9, ans=0;
  while (r-l>eps)
  {
    double mid = (l+r)/2;
    if (check(mid))
    {
      ans=mid;
      r=mid;
    } else l=mid;
  }
  cout << fixed << setprecision(6) << ans;
	return 0;
}

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