1697. RXD and numbers

时间限制 2000 ms   内存限制 512 MB

RXD has a sequence $A_1,A_2,A_3,\dots A_n$, which possesses the following properties:
- $1\leq A_i\leq m$
- $A_1 = A_n = 1$
- for all $1\leq x\leq m$, there is at least one position $p$ where $A_p = x$.
- for all $x, y$, the number of $i(1 \leq i < n)$ which satisfies $A_i = x ~ and ~ A_{i + 1} = y$ is $D_{x, y}$.
One day, naughty boy DXR clear the sequence.
RXD wants to know, how many valid sequences are there.
Output the answer module $998244353$.
$0\leq D_{i, j}<500,1\leq m\leq 400$
$n \geq 2$

输入数据

There are several test cases, please keep reading until EOF.
There are about 10 test cases, but only 1 of them satisfies $m > 50$
For each test case, the first line consists of 1 integer $m$, which means the range of the numbers in sequence.
For the next $m$ lines, in the $i$-th line, it consists of $m$ integers, the $j$-th integer means $D_{i, j}$.
We can easily conclude that $n = 1 + \sum_{i = 1}^{m}\sum_{j = 1}^{m}{D_{i, j}}$.

输出数据

For each test case, output "Case #x: y", which means the test case number and the answer.

样例输入

复制
2
1 2
2 1
4
1 0 0 2
0 3 0 1
2 1 0 0
0 0 3 1
4
0 1 0 0
1 0 0 0
0 0 0 1
0 0 1 0 \n
 · \n
 · \n
 \n
 · · · \n
 · · · \n
 · · · \n
 · · · \n
 \n
 · · · \n
 · · · \n
 · · · \n
 · · · \n

样例输出

复制
Case #1: 6
Case #2: 18
Case #3: 0    ·   · \n
    ·   ·  \n
    ·   · \n

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Source

2017 Multi-University Training Contest - Team 3

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