Problem:
Score : 400 points

Problem Statement

You are given N items.

The value of the i-th item (1 \leq i \leq N) is v_i.

Your have to select at least A and at most B of these items.

Under this condition, find the maximum possible arithmetic mean of the values of selected items.

Additionally, find the number of ways to select items so that the mean of the values of selected items is maximized.

Constraints

1 \leq N \leq 50

1 \leq A,B \leq N

1 \leq v_i \leq 10^{15}

Each v_i is an integer.

Input

The input is given from Standard Input in the following format:

N A B
v_1
v_2
...
v_N

Output

Print two lines.

The first line should contain the maximum possible arithmetic mean of the values of selected items. The output should be considered correct if the absolute or relative error is at most 10^{-6}.

The second line should contain the number of ways to select items so that the mean of the values of selected items is maximized.

Sample Input 1

5 2 2
1 2 3 4 5

Sample Output 1

4.500000
1

The mean of the values of selected items will be maximized when selecting the fourth and fifth items. Hence, the first line of the output should contain 4.5.

There is no other way to select items so that the mean of the values will be 4.5, and thus the second line of the output should contain 1.

Sample Input 2

4 2 3
10 20 10 10

Sample Output 2

15.000000
3

There can be multiple ways to select items so that the mean of the values will be maximized.

Sample Input 3

5 1 5
1000000000000000 999999999999999 999999999999998 999999999999997 999999999999996

Sample Output 3

1000000000000000.000000
1

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Text;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Threading.Tasks;

class Solve
{
	const int mod = 1000000007;
	static void Main(string[] args)
	{
		var input = Console.ReadLine().Split().Select(int.Parse).ToArray();
		int N = input[0];
		int A = input[1];
		int B = input[2];
		var v = Console.ReadLine().Split().Select(long.Parse).ToArray();

		decimal ans = 0;
		
		long cnt = 0;

		Array.Sort(v);
		Array.Reverse(v);
        for(var i = 0; i < A; i++)
		{
			ans = (i * ans + v[i]) / (i + 1);
		}
		
		int start = -1;
		int end = A - 1;
		bool same = false;

		for (var i = 0; i < N; i++) 
		{
			if (v[i] == v[A - 1] && start == -1) { start = i; }
			else if (v[i] == v[A - 1])  { end = i; }

			if (start == 0 && end > A - 1) { same = true; }
		}
		var c = new Calculation();
		if (same)
		{
			long sum = 0;

			for (int i = A - 1; i < Math.Min(B,end+1); i++)
			{
				sum += c.GetNCR(end + 1, i + 1);
			}
			cnt = sum;
		}
		else
		{
			cnt = c.GetNCR(end - start + 1, A - start);
		}
        

		Console.WriteLine(ans);
		Console.WriteLine(cnt);


		

	}
}

//var input = Console.ReadLine().Split().Select(int.Parse).ToArray();
//入力用

public class Calculation //各種値の計算メソッド
{
	public int GetGcd(int a, int b) //最大公約数(２数)
	{

		if (a < b)
		{
			int c = a;
			a = b;
			b = c;
		}
		if (b == 0)
		{
			return a;
		}
		int r = a % b;
		while (r > 0)
		{
			a = b;
			b = r;
			r = a % b;
		}
		return b;
	}
	public int GetGcdOfSortedArray(int[] array) //最大公約数(ソート済み数列)
	{
		if (array.Length == 0) { return 1; }
		else if (array.Length == 1) { return array[0]; }
		else
		{
			int n = 0;
			int g = array[0];
			while (n <= array.Length - 2)
			{

				int a = array[n + 1];
				int b = g;
				int r = a % b;
				while (r > 0)
				{
					a = b;
					b = r;
					r = a % b;
				}
				g = b;
				
			    n++;
			}

			return g;

		}
	}

	public long GetNCR(int n, int r) //二項係数(生の値)
	{
		if (n == 1) { return 1; }
		long[] nC = new long[n + 1];
		nC[0] = 1;
		for (var i = 0; i <= r - 1; i++)
		{
			nC[i + 1] = nC[i] * (n - i) / (i + 1);
		}
		return nC[r];
	}


}

class Modulo //1000000007で割る問題用
{
	private const int M = 1000000007;
	private readonly int[] m_facs;
	public int Mul(int a, int b) //掛け算
	{
		return (int)(Math.BigMul(a, b) % M);
	}
	public Modulo(int n)
	{
		m_facs = new int[n + 1];
		m_facs[0] = 1;
		for (int i = 1; i <= n; ++i)
		{
			m_facs[i] = Mul(m_facs[i - 1], i);
		}
	}
	public int Fac(int n)
	{
		return m_facs[n];
	}
	public int Pow(int a, int m) //累乗
	{
		switch (m)
		{
			case 0:
				return 1;
			case 1:
				return a;
			default:
				int p1 = Pow(a, m / 2);
				int p2 = Mul(p1, p1);
				return ((m % 2) == 0) ? p2 : Mul(p2, a);
		}
	}
	public int Div(int a, int b) //除算
	{
		return Mul(a, Pow(b, M - 2));
	}
	public int Ncr(int n, int r) //二項係数
	{
		if (n < r) { return 0; }
		if (n == r) { return 1; }
		int res = Fac(n);
		res = Div(res, Fac(r));
		res = Div(res, Fac(n - r));
		return res;
	}
	public Modulo() { }
}