Geometric Progression Subsequences Problem Statement

Given an array of ‘N’ integers, determine the number of subsequences of length 3 that form a geometric progression with a specified common ratio ‘R’.

Explanation:

A geometric progression (GP) or sequence is characterized by numbers that differ by a common ratio, such as 2, 4, 8, 16 with common ratio 2.

Note:

Return the answer modulo 10⁹ + 7, as the result may be very large.

Input:

The first line contains an integer T denoting the number of test cases.
For each test case, the first line shows two integers N and R, the number of elements in the array and the common ratio.
The second line of each test case comprises N space-separated integers representing the array elements.

Output:

For each test case, print the number of subsequences of length 3 having the common ratio R.

Example:

Input:

T = 1
N = 4, R = 2
Array = [2, 4, 8, 16]

Output:

1

Constraints:

• 1 <= T <= 50
• 3 <= N <= 10⁴
• 1 <= R <= 10⁴
• 1 <= A[i] <= 10⁹
• Time Limit: 1 sec