| 시간 제한 | 메모리 제한 | 제출 | 정답 | 맞힌 사람 | 정답 비율 |
|---|---|---|---|---|---|
| 2 초 | 512 MB | 2 | 2 | 2 | 100.000% |
An integer sequence $a$ is rebound sequence if there are three integers $i,ドル $j,ドル $k$ (1ドル \le i < j < k \le N$) satisfying $a_i > a_k > a_j$. You are given an integer sequence $s$. Your task is to count the number of rebound sequences that can be obtained by permuting the elements of $s$.
The input consists of a single test case in the format below.
$N$
$s_1$ $s_2$ $\dots$ $s_N$
The first line contains a single integer $N$ (1ドル \le N \le 200$). The second line contains $N$ integers $s_i$ (1ドル \le s_i \le N$), which is the $i$-th element of $s$.
Output the number of rebound sequences that can be obtained by permuting the elements of $s$ modulo 10ドル^9 + 7$.
4 1 2 3 4
10
12 1 2 3 4 5 6 7 8 9 10 11 12
478793588
5 3 1 4 1 5
32
20 1 1 1 2 3 4 4 7 7 8 11 12 13 14 15 16 17 17 19 20
959127228