A11129 | On the Bench
时间限制1s
内存限制256MB
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题目描述
A year ago on the bench in public park Leha found an array of $n$ numbers. Leha believes that permutation $p$ is right if for all $1<=i<n$ condition, that $a_{pi}·a_{pi+1}$ is not perfect square, holds. Leha wants to find number of right permutations modulo $10^{9}+7$ .
输入格式
First line of input data contains single integer $n$ ( $1<=n<=300$ ) — length of the array.
Next line contains $n$ integers $a_{1},a_{2},...\ ,a_{n}$ ( $1<=a_{i}<=10^{9}$ ) — found array.
Next line contains $n$ integers $a_{1},a_{2},...\ ,a_{n}$ ( $1<=a_{i}<=10^{9}$ ) — found array.
输出格式
Output single integer — number of right permutations modulo $10^{9}+7$ .
输入输出样例
输入 #1
3 1 2 4
输出 #1
2
输入 #2
7 5 2 4 2 4 1 1
输出 #2
144
For first example:
$[1,2,4]$ — right permutation, because $2$ and $8$ are not perfect squares.
$[1,4,2]$ — wrong permutation, because $4$ is square of $2$ .
$[2,1,4]$ — wrong permutation, because $4$ is square of $2$ .
$[2,4,1]$ — wrong permutation, because $4$ is square of $2$ .
$[4,1,2]$ — wrong permutation, because $4$ is square of $2$ .
$[4,2,1]$ — right permutation, because $8$ and $2$ are not perfect squares.
$[1,2,4]$ — right permutation, because $2$ and $8$ are not perfect squares.
$[1,4,2]$ — wrong permutation, because $4$ is square of $2$ .
$[2,1,4]$ — wrong permutation, because $4$ is square of $2$ .
$[2,4,1]$ — wrong permutation, because $4$ is square of $2$ .
$[4,1,2]$ — wrong permutation, because $4$ is square of $2$ .
$[4,2,1]$ — right permutation, because $8$ and $2$ are not perfect squares.
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评测结果：Accepted