Submission #1730972

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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<int> coin(n);
    for (int i = 0; i < n; i++) cin >> coin[i];
    sort(coin.begin(), coin.end());

    int size = coin.size();
    int cnt = 0;
    vector<bool> v(n);
    int init = 0;
    int kai = 0;
    do {
        for (int i = 0; i < n; i++) v[i] = true;

        init = 0;
        for (int i = init; i < size-1; i++) {
            for (int j = init+1; j < size; j++) {
                if (i == j) continue;
                // printf("(%d %d)\n", coin[i], coin[j]);
                if (coin[j] % coin[i] == 0) {
                    v[j] = !v[j];
                }
            }
            init++;
        }
        // cout << "-----------"  << endl;
        cnt += count(v.begin(), v.end(), true);
        kai++;
    } while( next_permutation(coin.begin(), coin.end()) );

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

    return 0;
}

Submission Info

Judge Result