Problem:
Score : 200 points

Problem Statement

Snuke has N sticks.
The length of the i-th stick is l_i.

Snuke is making a snake toy by joining K of the sticks together.

The length of the toy is represented by the sum of the individual sticks that compose it.
Find the maximum possible length of the toy.

Constraints

1 \leq K \leq N \leq 50

1 \leq l_i \leq 50

l_i is an integer.

Input

Input is given from Standard Input in the following format:

N K
l_1 l_2 l_3 ... l_{N}

Output

Print the answer.

Sample Input 1

5 3
1 2 3 4 5

Sample Output 1

12

You can make a toy of length 12 by joining the sticks of lengths 3, 4 and 5, which is the maximum possible length.

Sample Input 2

15 14
50 26 27 21 41 7 42 35 7 5 5 36 39 1 45

Sample Output 2

386

Solution in Go (1.6) (judge verdict: Time Limit Exceeded)

package main

import (
	"fmt"
)

var N, K, w, m int
var a []int

func main() {
	fmt.Scan(&N, &K)
	a = make([]int, N)
	for i := 0; i < N; i++ {
		fmt.Scan(&a[i])
	}
	fmt.Println(drf(0, 0, 0))
}

func drf(i int, w int, k int) int {
	if k >= K || i >= N {
		return w
	}
	p := drf(i+1, w, k)
	q := drf(i+1, w+a[i], k+1)
	return max(p, q)
}

func max(a, b int) int {
	if b > a {
		return b
	}
	return a
}