Submission #1913331

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Source Code Expand

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

#define DEBUG(x) cerr << #x << ": " << x << endl;
#define ll long long

int main() {
    int n;
    cin >> n;
    vector<ll> c(n);
    for (ll& x : c) {
        cin >> x;
    }

    sort(c.begin(), c.end());
    int cnt = 0;
    int a = 0;
    do {
        vector<bool> v(n, true);
        for (int i = 0; i < n-1; i++) {
            for (int j = i+1; j < n; j++) {
                if (c[j] % c[i] == 0) {
                    v[j] = !v[j];
                }
            }
        }
        cnt++;
        a += count(v.begin(), v.end(), true);
    } while (next_permutation(c.begin(), c.end()));

    printf("%.10f\n", (double)a / cnt);

    return 0;
}

Submission Info

Judge Result