题目描述
Problem Description
You are given a pair of integer sequences of length $N$, $A=(A_1, A_2, \dots, A_N)$ and $B=(B_1, B_2, \dots, B_N)$. Initially, for all $i = 1, 2, \dots, N$, $A_i = B_i = 0$.
You will perform the following operation $M$ times on $A$ and $B$:
- Operation: Choose integers $i, j$ ($1 \le i, j \le N$), and increment $A_i$ and $B_j$ by $1$.
However, among the $M$ operations, exactly $X$ operations must satisfy $i = j$.
Find the number of possible pairs of sequences $A$ and $B$ after $M$ operations, modulo $998244353$.
Input Format
The input is given from the standard input in the following format:
$N\ M\ X$
Output Format
Output the number of possible pairs of sequences $A$ and $B$ after $M$ operations, modulo $998244353$.
Sample Input and Output
Sample Input #1
3 1 1
Sample Output #1
3
Sample Input #2
3 1 0
Sample Output #2
6
Sample Input #3
4 4 2
Sample Output #3
643
Sample Input #4
314 1592 653
Sample Output #4
755768689
Notes/Hints
Constraints
- $2 \leq N \leq 3000$
- $0 \leq X \leq M \leq 3000$
- All inputs are integers
Sample Explanation 1
The following $3$ pairs:
- $A=(1,0,0), B=(1,0,0)$
- $A=(0,1,0), B=(0,1,0)$
- $A=(0,0,1), B=(0,0,1)$
Sample Explanation 2
The following $6$ pairs:
- $A=(1,0,0), B=(0,1,0)$
- $A=(1,0,0), B=(0,0,1)$
- $A=(0,1,0), B=(1,0,0)$
- $A=(0,1,0), B=(0,0,1)$
- $A=(0,0,1), B=(1,0,0)$
- $A=(0,0,1), B=(0,1,0)$
Sample Explanation 3
For example, the following pairs of $A$ and $B$ are possible:
- $A=(1,1,1,1), B=(1,1,1,1)$
- $A=(1,0,0,3), B=(0,1,0,3)$
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分