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 (1.14.1) (judge verdict: Accepted)

package main

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

func scanInt() int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return i
}

func scanInt64() int64 {
	sc.Scan()
	i, _ := strconv.ParseInt(sc.Text(), 10, 64)
	return i
}

func scanInts(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = scanInt()
	}
	return res
}

func scanInts64(n int) []int64 {
	res := make([]int64, n)
	for i := range res {
		res[i] = scanInt64()
	}
	return res
}

func scanText() string {
	sc.Buffer([]byte{}, math.MaxInt64)
	sc.Scan()
	return sc.Text()
}

var sc = bufio.NewScanner(os.Stdin)

func main() {
	sc.Split(bufio.ScanWords)
	n, m := scanInt(), scanInt()

	a := scanInts(n)
	sort.Sort(sort.Reverse(sort.IntSlice(a)))
	sum := 0

	for i := 0; i < n; i++ {
		sum += a[i]
	}

	for i := 0; i < m; i++ {
		if 4*m*a[i] < sum {
			fmt.Println("No")
			return
		}
	}
	fmt.Println("Yes")
}