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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<int,int> Pii;
typedef pair<ll, ll> Pll;
typedef pair<int, Pii > P1;

#define rep(i,n) for(int i=0;i<n;i++)
#define sor(v) sort(v.begin(),v.end())
#define rev(s) reverse(s.begin(),s.end())
#define lb(vec,a) lower_bound(vec.begin(),vec.end(),a)
#define ub(vec,a) upper_bound(vec.begin(),vec.end(),a)
#define mp1(a,b,c) P1(a,P(b,c))
#define get_arsize(a) (sizeof(a)/sizeof(a[0]))

const ll MOD = 1000000007;
const double EPS = 1e-10;
const int MAX = 200000;

int main() {
  int n, m;
  cin >> n >> m;
  vector<int> av;
  ll sum = 0;
  rep(i,n) {
    int a;
    cin >> a;
    av.push_back(a);
    sum += a;
  }
  int cnt = 0;
  double d = (double) sum / (double) (4*m);
  rep(i,n) {
    if ((double)av[i] >= d) cnt++;
  }
  if(cnt >= m) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
  return 0;
}