Submission #1943649

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Source Code Expand

#include <bits/stdc++.h>
#define rep(i, a, n) for(int i = a; i < n; i++)
#define repb(i, a, b) for(int i = a; i >= b; i--)
#define all(a) a.begin(), a.end()
#define o(a) cout << a << endl
#define int long long
#define fi first
#define se second
using namespace std;
typedef pair<int, int> P;

signed main(){
    int n;
    cin >> n;
    vector<int> c(n);
    rep(i, 0, n){
        cin >> c[i];
    }
    double ans = 0.0;
    rep(i, 0, n){
        int cnt = 0;
        rep(j, 0, n){
            if(c[i] % c[j] == 0) cnt++;
        }
        if(cnt % 2 == 0) ans += 0.5;
        else ans += (cnt / 2 + 1.0) / (double)cnt;
    }
    printf("%.10lf\n", ans);
}

Submission Info

Judge Result