Submission #3975490

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Source Code Expand

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

signed main(){
  int N;
  cin>>N;
  std::vector<int> v(N);
  for(int i=0;i<N;i++)cin>>v[i];
  sort(v.begin(),v.end());
  std::vector<int> w(N,0);
  for(int i=N-1;i>=0;i--){
    for(int j=N-1;j>=0;j--){
      if(v[i]%v[j]==0)w[i]++;
    }
  }
  double ans=0;
  for(int i=0;i<N;i++){
    if(w[i]==1){ans++;continue;}
    int a=w[i]/2;
    a=w[i]-a;
    double b=a;
    double c=w[i];
    b/=c;
    ans+=b;
  }
  cout<<fixed<<setprecision(12)<<ans<<endl;
}

Submission Info

Judge Result