Problem:
Score : 200 points

Problem Statement

We have held a popularity poll for N items on sale. Item i received A_i votes.

From these N items, we will select M as popular items. However, we cannot select an item with less than \dfrac{1}{4M} of the total number of votes.

If M popular items can be selected, print Yes; otherwise, print No.

Constraints

1 \leq M \leq N \leq 100

1 \leq A_i \leq 1000

A_i are distinct.

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N M
A_1 ... A_N

Output

If M popular items can be selected, print Yes; otherwise, print No.

Sample Input 1

4 1
5 4 2 1

Sample Output 1

Yes

There were 12 votes in total. The most popular item received 5 votes, and we can select it.

Sample Input 2

3 2
380 19 1

Sample Output 2

No

There were 400 votes in total. The second and third most popular items received less than \dfrac{1}{4\times 2} of the total number of votes, so we cannot select them. Thus, we cannot select two popular items.

Sample Input 3

12 3
4 56 78 901 2 345 67 890 123 45 6 789

Sample Output 3

Yes

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

using System;
using System.Collections.Generic;

namespace tst
{
    class Program
    {
        public static void Main()
        {
            string[] In1 = Console.ReadLine().Split(' ');
            int n = int.Parse(In1[0]);
            int m = int.Parse(In1[1]);
            string[] In2 = Console.ReadLine().Split(' ');
            int[] A = new int[n];
            int sum = 0;
            for(int i=0; i<n; i++)
            {
                A[i] = int.Parse(In2[i]);
                sum += A[i];
            }
            double border = sum / (4.0 * m);
            int cnt = 0;
            for(int i=0; i<n; i++)
            {
                if (A[i] >= border) cnt++;
            }
            if (cnt >= m)
            {
                Console.WriteLine("Yes");
            }
            else
            {
                Console.WriteLine("No");
            }
        }
    }
}