Count Seconds
Description
Cirno has a DAG (Directed Acyclic Graph) with $n$ nodes and $m$ edges. The graph has exactly one node that has no out edges. The $i$-th node has an integer $a_i$ on it.
Every second the following happens:
- Let $S$ be the set of nodes $x$ that have $a_x > 0$.
- For all $x \in S$, $1$ is subtracted from $a_x$, and then for each node $y$, such that there is an edge from $x$ to $y$, $1$ is added to $a_y$.
Find the first moment of time when all $a_i$ become $0$. Since the answer can be very large, output it modulo $998\,244\,353$.
The first line contains a single integer $t$ ($1 \leq t \leq 1000$) — the number of test cases. Description of test cases follows.
The first line of each test case contains two integers $n, m$ ($1 \leq n, m \leq 1000$) — the number of vertices and edges in the graph.
The second line of each test case contains $n$ integers $a_1, a_2, \ldots, a_n$ ($0 \leq a_i \leq 10^9$) — the integer on vertices.
Each line of the following $m$ lines contains two integers $x, y$ ($1 \leq x, y \leq n$), represent a directed edge from $x$ to $y$. It is guaranteed that the graph is a DAG with no multi-edges, and there is exactly one node that has no out edges.
It is guaranteed that both sum of $n$ and sum of $m$ over all test cases are less than or equal to $10\,000$.
For each test case, print an integer in a separate line — the first moment of time when all $a_i$ become $0$, modulo $998\,244\,353$.
Input
The first line contains a single integer $t$ ($1 \leq t \leq 1000$) — the number of test cases. Description of test cases follows.
The first line of each test case contains two integers $n, m$ ($1 \leq n, m \leq 1000$) — the number of vertices and edges in the graph.
The second line of each test case contains $n$ integers $a_1, a_2, \ldots, a_n$ ($0 \leq a_i \leq 10^9$) — the integer on vertices.
Each line of the following $m$ lines contains two integers $x, y$ ($1 \leq x, y \leq n$), represent a directed edge from $x$ to $y$. It is guaranteed that the graph is a DAG with no multi-edges, and there is exactly one node that has no out edges.
It is guaranteed that both sum of $n$ and sum of $m$ over all test cases are less than or equal to $10\,000$.
Output
For each test case, print an integer in a separate line — the first moment of time when all $a_i$ become $0$, modulo $998\,244\,353$.
Samples
5
3 2
1 1 1
1 2
2 3
5 5
1 0 0 0 0
1 2
2 3
3 4
4 5
1 5
10 11
998244353 0 0 0 998244353 0 0 0 0 0
1 2
2 3
3 4
4 5
5 6
6 7
7 8
8 9
9 10
1 3
7 9
5 6
1293 1145 9961 9961 1919
1 2
2 3
3 4
5 4
1 4
2 4
6 9
10 10 10 10 10 10
1 2
1 3
2 3
4 3
6 3
3 5
6 5
6 1
6 2
3
5
4
28010
110
Note
In the first test case:
- At time $0$, the values of the nodes are $[1, 1, 1]$.
- At time $1$, the values of the nodes are $[0, 1, 1]$.
- At time $2$, the values of the nodes are $[0, 0, 1]$.
- At time $3$, the values of the nodes are $[0, 0, 0]$.
So the answer is $3$.
- In the second test case:
- At time $0$, the values of the nodes are $[1, 0, 0, 0, 0]$.
- At time $1$, the values of the nodes are $[0, 1, 0, 0, 1]$.
- At time $2$, the values of the nodes are $[0, 0, 1, 0, 0]$.
- At time $3$, the values of the nodes are $[0, 0, 0, 1, 0]$.
- At time $4$, the values of the nodes are $[0, 0, 0, 0, 1]$.
- At time $5$, the values of the nodes are $[0, 0, 0, 0, 0]$.
In the third test case:
The first moment of time when all $a_i$ become $0$ is $6\cdot 998244353 + 4$.