题库练习 Complex Market Analysis
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A14738 | Complex Market Analysis

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题目描述

![](/uploads/acgo/image/8917247c81a171f2_d1a5fdfefdb1.jpeg)While performing complex market analysis William encountered the following problem:

For a given array $a$ of size $n$ and a natural number $e$ , calculate the number of pairs of natural numbers $(i, k)$ which satisfy the following conditions:

- $1 \le i, k$
- $i + e \cdot k \le n$ .
- Product $a_i \cdot a_{i + e} \cdot a_{i + 2 \cdot e} \cdot \ldots \cdot a_{i + k \cdot e} $ is a prime number.

A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers.

输入格式

Each test contains multiple test cases. The first line contains the number of test cases $t$ ( $1 \le t \le 10\,000$ ). Description of the test cases follows.

The first line of each test case contains two integers $n$ and $e$ $(1 \le e \le n \le 2 \cdot 10^5)$ , the number of items in the array and number $e$ , respectively.

The second line contains $n$ integers $a_1, a_2, \dots, a_n$ $(1 \le a_i \le 10^6)$ , the contents of the array.

It is guaranteed that the sum of $n$ over all test cases does not exceed $2 \cdot 10^5$ .

输出格式

For each test case output the answer in the following format:

Output one line containing the number of pairs of numbers $(i, k)$ which satisfy the conditions.

输入输出样例

输入 #1
6
7 3
10 2 1 3 1 19 3
3 2
1 13 1
9 3
2 4 2 1 1 1 1 4 2
3 1
1 1 1
4 1
1 2 1 1
2 2
1 2
输出 #1
2
0
4
0
5
0
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