Submission #3975646

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)

int n;
double ans = 0;

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);

	cin >> n;
	vector<int> v(n);
	for(auto &x : v){
		cin >> x;
	}	

  	REP(i,n){
    	int temp = 0;
		REP(j,n){
      		if (i == j) continue;
      		temp += v[i] % v[j] == 0;
    	}
    	if (temp % 2){
			 ans += 0.5;
		}else{
			ans += (temp + 2.0) / (2 * temp + 2);
		} 
  }
	cout << fixed << setprecision(12)<< ans << endl;

}

Submission Info

Judge Result