题目描述
Problem Statement
You are given a multiset of integers with N elements: $A=\lbrace A_1,A_2,...,A_N \rbrace$. It is guaranteed that every element of A is between 1 and M (inclusive).
Let us repeat the following operation K times.
- Choose an integer between 1 and M (inclusive) and add it to A. Then, delete the X-th smallest value in A.
Here, the X-th smallest value in A is the X-th value from the front in the sequence of the elements of A sorted in non-decreasing order.
There are M^K ways to choose an integer K times between 1 and M. Assume that, for each of these ways, we have found the sum of the elements of A after the operations with the corresponding choices. Find the sum, modulo 998244353, of the M^K values computed.
Input
Input is given from Standard Input in the following format:
N M K X
$A_1 A_2 \dots A_N$
Output
Print the answer.
Constraints
- $1 \le N,M,K \le 2000$
- $1 \le X \le N+1$
- $1 \le A_i \le M$
- All values in input are integers.
Sample Input 1
2 4 2 1
1 3
Sample Output 1
99
We start with A={1,3}. Here is an example of how we do the operations.
-
Add 4 to A, making A={1,3,4}. Then, delete the 1-st smallest value, making A={3,4}.
-
Add 3 to A, making A={3,3,4}. Then, delete the 1-st smallest value, making A={3,4}.
In this case, the sum of the elements of A after the operations is 3+4=7.
Sample Input 2
5 9 6 3
3 7 1 9 9
Sample Output 2
15411789
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分