write a go solution for Description:
You are given two arrays a and b each consisting of n integers. All elements of a are pairwise distinct.

Find the number of ways to reorder a such that a_i>b_i for all 1<=i<=n, modulo 10^9+7.

Two ways of reordering are considered different if the resulting arrays are different.

Input Format:
Each test contains multiple test cases. The first line contains the number of test cases t (1<=t<=10^4). The description of the test cases follows.

The first line of each test case contains a single integer n (1<=n<=2*10^5) — the length of the array a and b.

The second line of each test case contains n distinct integers a_1, a_2, ldots, a_n (1<=a_i<=10^9) — the array a. It is guaranteed that all elements of a are pairwise distinct.

The second line of each test case contains n integers b_1, b_2, ldots, b_n (1<=b_i<=10^9) — the array b.

It is guaranteed that the sum of n over all test cases does not exceed 2*10^5.

Output Format:
For each test case, output the number of ways to reorder array a such that a_i>b_i for all 1<=i<=n, modulo 10^9+7.

Note:
None. Output only the code with no comments, explanation, or additional text.