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: Wrong Answer)

package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	sc.Scan()
	N, _ := strconv.Atoi(sc.Text())

	sc.Scan()
	M, _ := strconv.Atoi(sc.Text())

	total := 0
	a := make([]int, N)
	for i := range a {
		sc.Scan()
		a[i], _ = strconv.Atoi(sc.Text())
		total = total + a[i]
	}

	var min float64 = float64(total) / float64(4.0*M)

	for _, a := range a {
		if float64(a) > min {
			M = M - 1
		}
	}

	if M <= 0 {
		fmt.Println("Yes")
	} else {
		fmt.Println("No")
	}
}