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Description:

A permutation of length $$$n$$$ is an array consisting of $$$n$$$ distinct integers from $$$1$$$ to $$$n$$$ in arbitrary order. For example, $$$[2,3,1,5,4]$$$ is a permutation, but $$$[1,2,2]$$$ is not a permutation ($$$2$$$ appears twice in the array), and $$$[1,3,4]$$$ is also not a permutation ($$$n=3$$$ but there is $$$4$$$ in the array). There are $$$n! = n \cdot (n-1) \cdot (n - 2) \cdot \ldots \cdot 1$$$ different permutations of length $$$n$$$.

Given a permutation $$$p$$$ of $$$n$$$ numbers, we create an array $$$a$$$ consisting of $$$2n$$$ numbers, which is equal to $$$p$$$ concatenated with its reverse. We then define the beauty of $$$p$$$ as the number of inversions in $$$a$$$.

The number of inversions in the array $$$a$$$ is the number of pairs of indices $$$i$$$, $$$j$$$ such that $$$i < j$$$ and $$$a_i > a_j$$$.

For example, for permutation $$$p = [1, 2]$$$, $$$a$$$ would be $$$[1, 2, 2, 1]$$$. The inversions in $$$a$$$ are $$$(2, 4)$$$ and $$$(3, 4)$$$ (assuming 1-based indexing). Hence, the beauty of $$$p$$$ is $$$2$$$.

Your task is to find the sum of beauties of all $$$n!$$$ permutations of size $$$n$$$. Print the remainder we get when dividing this value by $$$1\,000\,000\,007$$$ ($$$10^9 + 7$$$).

Input:

Each test contains multiple test cases. The first line contains the number of test cases $$$t$$$ ($$$1 \le t \le 10^5$$$). The description of the test cases follows.

Each test case has only one line — the integer $$$n$$$ ($$$1 \leq n \leq 10^5$$$).

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

Output:

For each test case, print one integer — the sum of beauties of all permutations of size $$$n$$$ modulo $$$1\,000\,000\,007$$$ ($$$10^9 + 7$$$).

Sample Input:

3
1
2
100

Sample Output:

0
4
389456655

Note:

For the first test case of the example, $$$p = [1]$$$ is the only permutation. $$$a = [1, 1]$$$ has $$$0$$$ inversions.

For the second test case of the example, the permutations are $$$[1, 2]$$$ and $$$[2, 1]$$$. Their respective $$$a$$$ arrays are $$$[1, 2, 2, 1]$$$ and $$$[2, 1, 1, 2]$$$, both of which have $$$2$$$ inversions.

Informação

Codeforces

Provedor Codeforces

Código CF1777B

Tags

combinatoricsgreedymath

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Datas 09/05/2023 10:35:45

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