题目描述
Problem Description
Xiaoxue and Xiaoke are playing a number game. They have prepared $n$ cards, each with an integer on it. At the start of the game, Xiaoxue will choose an integer $t$ that is not less than $a$ and not greater than $b$, and tell Xiaoke this number $t$. Then, Xiaoke will select exactly $k$ cards and sum the numbers on these $k$ cards to get a sum $m$.
Xiaoxue wants the absolute difference between $t$ and $m$ to be as large as possible, while Xiaoke wants the absolute difference between $t$ and $m$ to be as small as possible. Before the game starts, both of them know the values of $n$, $a$, $b$, and $k$, as well as the numbers on each card. After Xiaoxue decides the value of $t$, it cannot be changed, and then Xiaoke will select the cards.
Xiaoxue wants to know, under the optimal strategies of both players, what is the maximum possible absolute difference between $t$ and $m$?
Input Format
The input consists of two lines.
The first line contains 4 integers $n$, $k$, $a$, and $b$, satisfying $1 \le k \le n \le 250$ and $0 \le a \le b \le 75000$.
The second line contains $n$ integers, representing the numbers on each card from $x_1$ to $x_n$.
Each card's number $x_i$ satisfies $0 \le x_i \le 300$.
Output Format
Output a single line with a single integer, representing the maximum possible absolute difference between $t$ and $m$.
Sample Input and Output
Sample Input #1
4 2 58 100
10 10 50 80
Sample Output #1
15
Sample Input #2
8 3 1300 1800
2 0 1 9 1 4 0 5
Sample Output #2
1782
Notes/Hints
For 30% of the data, $1 \le k \le n \le 20$ and $0 \le a \le b \le 6000$.
For 80% of the data, $1 \le k \le n \le 65$ and $0 \le a \le b \le 19650$.
For 100% of the data, $1 \le k \le n \le 250$ and $0 \le a \le b \le 75000$.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分