Submission #1308556

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Source Code Expand

#include <bits/stdc++.h>

using namespace std;

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int n;
	cin >> n;
	vector<int> c(n);
	for (int i = 0; i < n; i++) cin >> c[i];
	double ans = 0;
	for (int i = 0; i < n; i++) {
		int cnt = 0;
		for (int j = 0; j < n; j++) {
			cnt += (c[i] % c[j] == 0);
		}
		if (cnt % 2 == 0) ans += 0.5;
		else ans += (cnt + 1) / 2 * 1.0 / cnt;
	}
	cout << setprecision(10) << ans << endl;
	return 0;
}

Submission Info

Judge Result