Submission #169614

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Source Code Expand

#include <iostream>
#include <algorithm>
#include <vector>

using namespace std;

#define rep(i, n) for(int i = 0; i < n; i++)

int n;
int cnt = 0;

void solve(vector<int> nums){
	int coins[100];
	rep(k, n) coins[k] = 1;
	for(int j = 0; j < n-1; j++){
		for(int k = j+1; k < n; k++){
			if(nums[k] % nums[j] == 0){
				coins[k] *= -1;
			}
		}
	}

	rep(j, n){
		if(coins[j] == 1) cnt++;
	}

	/*
	rep(j, n){
		cout << nums[j] << " ";
	}
	cout << endl;
	*/

}

void perm(vector<int> nums, int d, int md){
	if(md <= d){
		solve(nums);
		return;
	}
	
	int num = d;
	while(num < md){
		swap(nums[d], nums[num]);
		perm(nums, d+1, md);
		swap(nums[d], nums[num]);
		num++;
	}
	return;
	
}


int main(int argc, char const* argv[])
{
	
	cin >> n;
	vector<int> nums(n);
	rep(i, n) cin >> nums[i];
	
	int fact = 1;
	rep(i, n) fact *= (i+1);
	
	perm(nums, 0, n);

	cout << (double)cnt / fact << endl;


	return 0;
}

Submission Info

Judge Result