7029.Square Subsets

Time Limit: 1s Memory Limit: 512MB

Given an array of $n$ integers, count the number of subsets whose elements' product is a square number.

Also count the empty subset with product equal to one.

Input Format(From the terminal/stdin)

The first line has an integer $n$ : the size of the array.

The next line has $n$ integers $x_1, x_2,\dots, x_n$ : the contents of the array.

  • $1 \le n \le 5000$
  • $1 \le x_i \le 5000$

Output Format(To the terminal/stdout)

Print one integer: the answer to the problem modulo $10^9 + 7$ .

Sample Input

Copy
4
2 2 3 6
 \n
 · · · \n

Sample Output

Copy
4
 \n
Source: CSES, Additional Problems I, 3193

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