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 Go (1.6) (judge verdict: Accepted)

package main

import(
  "fmt"
)

func main() {
  var N,M int
  fmt.Scan(&N,&M)

  A := make([]int, N)
  sum := 0
  for v := range A{
	fmt.Scan(&A[v])
	sum += A[v]
  }

  var border int
  if sum%(4*M) == 0 {
	border = sum/(4*M) -1
  } else {
	border = sum/(4*M)
  }

  count := 0
  for _,v:= range A {
	if v >border {
	  count++
	}
  }

  if count >= M {
	fmt.Println("Yes")
  } else {
	fmt.Println("No")
  }
}