| Codeforces Round 1069 (Div. 1) |
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| Finished |
The master creates a composition of $$$n$$$ colored mosaic elements. Each element is painted in one of $$$m$$$ possible colors (the colors are numbered from $$$1$$$ to $$$m$$$).
The master arranges the composition in such a way that it can be represented as a tree.
The composition is considered beautiful if for each color $$$i$$$, the total degree of all vertices of color $$$i$$$ has a specified parity $$$\mathrm{mask}_i$$$, where $$$\mathrm{mask}$$$ is an array of $$$m$$$ numbers $$$0$$$ or $$$1$$$.
Help the master count the number of ways to create a beautiful composition. Output the answer modulo $$$10^9 + 7$$$.
Each test contains multiple test cases. The first line contains the number of test cases $$$t$$$ ($$$1 \le t \le 100$$$). The description of the test cases follows.
The first line of each test case contains two integers $$$n$$$ and $$$m$$$ ($$$1 \le n, m \le 10^4$$$) — the number of vertices and the number of possible colors, respectively.
The second line of each test case contains $$$n$$$ integers $$$c_i$$$ ($$$1 \le c_i \le m$$$) — the color of vertex $$$i$$$.
The third line of each test case contains $$$m$$$ integers $$$\mathrm{mask}_i$$$ ($$$\mathrm{mask}_i \in \{0, 1\}$$$) — the parity of color $$$i$$$ (if the total degree of vertices of color $$$i$$$ should be even, $$$\mathrm{mask}_i = 0$$$, otherwise — $$$\mathrm{mask}_i = 1$$$).
It is guaranteed that the sum of the values of $$$n$$$ across all test cases does not exceed $$$10^4$$$, and it is also guaranteed that the sum of the values of $$$m$$$ across all test cases does not exceed $$$10^4$$$.
For each test case, output a single integer on a separate line — the number of ways to create a beautiful composition modulo $$$10^9 + 7$$$.
54 21 2 1 20 04 11 1 1 115 11 1 1 1 106 41 2 1 2 1 40 1 0 11 331 0 0
801253840
In the first test case, a valid example of a tree would be described by the edges $$$\{(1, 2), (1, 3), (1, 4)\}$$$. Here, the degrees are $$$3, 1, 1, 1$$$ respectively. Here, the total degree of vertices with colour $$$1$$$ is $$$4$$$ which is $$$0$$$ mod $$$2$$$, and similarly, the total degree of vertices with colour $$$2$$$ is $$$2$$$ which is also $$$0$$$ mod $$$2$$$, as required by the statement.
An example of an invalid tree would be described by the edges $$$\{(1, 2), (2, 3), (3, 4)\}$$$ as vertices with colour $$$1$$$ have degrees adding to $$$3$$$, which is odd.
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