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  1. #define _GLIBCXX_FILESYSTEM
  2. #include <bits/stdc++.h>
  3. using namespace std;
  4. #define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  5. #define ll long long
  6.  
  7.  
  8. double pos[100001];
  9. double v[100001];
  10.  
  11. int n;
  12.  
  13. double calc(double x)
  14. {
  15.  
  16.     double t=-1e17;
  17.     for(int i=0;i<n;i++)
  18.     {
  19.         t=max(t,abs(pos[i]-x)/v[i]);
  20.  
  21.     }
  22.     return t;
  23. }
  24.  
  25. int main()
  26. {
  27.  
  28.      IOS
  29.     cin>>n;
  30.     double mx=INT_MIN;
  31.     for(int i=0;i<n;i++)
  32.     {
  33.         cin>>pos[i]>>v[i];
  34.         mx=max(mx,pos[i]);
  35.     }
  36.  
  37.     double l=-mx-20;
  38.     double r=mx+20;
  39.  
  40.     if(n==1)
  41.     {
  42.         cout<<0<<"\n";
  43.         return 0;
  44.     }
  45.     for(int i=0;i<300;i++)
  46.     {
  47.  
  48.         double mid1=l+(r-l)/3.0;
  49.         double mid2 = r - (r - l) / 3.0;
  50.  
  51.         double m1=calc(mid1);
  52.         double m2=calc(mid2);
  53.  
  54.         if(m2<m1)
  55.              l=mid1;
  56.         else
  57.             r=mid2;
  58.     }
  59.     cout<<fixed<<setprecision(10)<<calc(r)<<"\n";
  60.  
  61. }
  62.  
  63.  
  64.  
  65.  
  66.  
  67.  
Success #stdin #stdout 0s 5300KB
comments (?)
stdin 
5
-1 5
10 3
4 2
7 10
8 1
stdout 
1.5000000000
https://ideone.com/8IUiWq
language:
C++14 (gcc 8.3)
created:
12 days ago
visibility:
public

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