Submission #169620

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Source Code Expand

#include <iostream>
#include <algorithm>
#include <vector>
#include <bitset>
using namespace std;

int fact(int n){
	if(n == 0)
		return 1;
	else
		return n * fact(n - 1);
}

int main() {
	int n;
	cin >> n;
	int c;
	vector<int> coin;
	for(int i = 0; i < n; ++i){
		cin >> c;
		coin.push_back(c);
	}
	
	bitset<100> bits;
	int count = 0;
	do{
		bits.set();
		int cnt = 0;
		while(cnt < n - 1){
			for(int i = cnt + 1; i < n; ++i){
				if(coin[i] % coin[cnt] == 0){
					bits.flip(i);
				}
			}
			cnt++;
		}
		count += bits.count() - (100 - n);
	}while(next_permutation(coin.begin(), coin.end()));
	
	double ans = double(count) / fact(n);
	cout << fixed << ans << endl;
	
	return 0;
}

Submission Info

Judge Result