Submission #1241223

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Source Code Expand

#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cmath>
#include<math.h>
#include<string>
#include<string.h>
#include<stack>
#include<queue>
#include<vector>
#include<utility>
#include<set>
#include<map>
#include<stdlib.h>
#include<iomanip>

using namespace std;

#define ll long long
#define ld long double
#define EPS 0.0000000001
#define INF 1e9
#define MOD 1000000007
#define rep(i,n) for(i=0;i<n;i++)
#define loop(i,a,n) for(i=a;i<n;i++)
#define all(in) in.begin(),in.end()
#define shosu(x) fixed<<setprecision(x)

typedef vector<int> vi;
typedef pair<int,int> pii;

int main(void) {
  int i,j;
  int n;
  cin>>n;
  double ans=0;
  vi c(n);
  rep(i,n)cin>>c[i];
  rep(i,n){
    int s=0;
    rep(j,n)
      if(i!=j && c[i]%c[j]==0)s++;
    if(s%2)ans+=0.5;
    else ans+=1.0*(s+2)/(2*s+2);
  }
  cout<<shosu(10)<<ans<<endl;
}

Submission Info

Judge Result