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"
	"strings"
)

// 文字列を1行入力
func StrStdin() (stringReturned string) {
	scanner := bufio.NewScanner(os.Stdin)

	scanner.Scan()
	stringReturned = scanner.Text()

	stringReturned = strings.TrimSpace(stringReturned)
	return
}

// 空白や空文字だけの値を除去したSplit()
func SplitWithoutEmpty(stringTargeted string, delim string) (stringReturned []string) {
	stringSplited := strings.Split(stringTargeted, delim)

	for _, str := range stringSplited {
		if str != "" {
			stringReturned = append(stringReturned, str)
		}
	}
	return
}

// デリミタで分割して文字列スライスを取得
func SplitStrStdin(delim string) (stringReturned []string) {
	// 文字列で1行取得
	stringInput := StrStdin()

	// 空白で分割
	// stringSplited := strings.Split(stringInput, delim)
	stringReturned = SplitWithoutEmpty(stringInput, delim)

	return
}

// デリミタで分割して整数値スライスを取得
func SplitIntStdin(delim string) (intSlices []int, err error) {
	// 文字列スライスを取得
	stringSplited := SplitStrStdin(" ")

	// 整数スライスに保存
	for i := range stringSplited {
		var iparam int
		iparam, err = strconv.Atoi(stringSplited[i])
		if err != nil {
			return
		}
		intSlices = append(intSlices, iparam)
	}
	return
}

func main() {
	input, _ := SplitIntStdin(" ")
	_, M := input[0], input[1]

	input, _ = SplitIntStdin(" ")

	sum := 0
	for _, x := range input {
		sum += x
	}

	var M_f float64 = float64(M)
	var sum_f float64 = float64(sum)

	count := 0
	for _, x := range input {
		var x_f float64 = float64(x)
		if x_f >= sum_f/(4.0*M_f) {
			count += 1
		}
	}

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

}