Problem8148--USACO 2022 January Contest, Platinum Problem 2. Counting Haybales

8148: USACO 2022 January Contest, Platinum Problem 2. Counting Haybales

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Time Limit : 1.000 sec  Memory Limit : 256 MiB

Description

As usual, Bessie the cow is causing trouble in Farmer John's barn. FJ has N (1≤N≤5000) stacks of haybales. For each i∈[1,N], the i-th stack has $h_i\ (1≤h_i≤10^9)$ haybales. Bessie does not want any haybales to fall, so the only operation she can perform is as follows:
  • If two adjacent stacks' heights differ by exactly one, she can move the top haybale of the taller stack to the shorter stack.
How many configurations are obtainable after performing the above operation finitely many times, modulo $10^9+7$? Two configurations are considered the same if, for all i, the i-th stack has the same number of haybales in both.

Input

The first line contains T (1≤T≤10), the number of independent test cases, all of which must be solved to solve one input correctly. Each test case consists of N.
Then a sequence of N heights. It is guaranteed that the sum of N over all test cases does not exceed 5000.

Output

Please output T lines, one for each test case.

Sample 1 Input

7
4
2 2 2 3
4
3 3 1 2
4
5 3 4 2
6
3 3 1 1 2 2
6
1 3 3 4 1 2
6
4 1 2 3 5 4
10
1 5 6 6 6 4 2 3 2 5

Sample 1 Output

4
4
5
15
9
8
19

For the first test case, the four possible configurations are:

(2,2,2,3),(2,2,3,2),(2,3,2,2),(3,2,2,2).

For the second test case, the four possible configurations are:

(2,3,3,1),(3,2,3,1),(3,3,2,1),(3,3,1,2).

HINT

相同题目:USACO Platinum

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