Submission #7103718

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Source Code Expand

#include <bits/stdc++.h>
#define ll long long
#define rep(X,N) for(ll X = 0; X < (N); X++)
#define pback push_back
#define mpair make_pair
#define MODN 1000000007

using namespace std;

int main(){

    int n;
    cin >> n;

    vector<int> c;

    rep(i,n){
        int tmp;
        cin >> tmp;

        c.pback(tmp);
    }

    double p = 0.0;

    rep(i,n){
        int tmp = c[i];

        int s = 0;

        for(int j = 0; j < n; j++){
            if(i != j && tmp % c[j] == 0) s++;
        }

        if(s % 2 == 1){
            p += 0.5;
        }else{
            p += ((double)(s + 2) / (2 * s + 2));
        }
    }

    cout << setprecision(10) << p << endl;
    return 0;
}

Submission Info

Judge Result