# Count Equal and Divisible Pairs in an Array

Easy

8

1

61.4% Acceptance

In this lab, you will be implementing a function that finds the number of pairs in an array that meet specific conditions. Given a **0-indexed** integer array `nums`

of length `n`

and an integer `k`

, your task is to return the **number of pairs** `(i, j)`

where `0 <= i < j < n`

, such that `nums[i] == nums[j]`

and `(i * j)`

is divisible by `k`

.

## Function signature:

`/** * @param {number[]} nums * @param {number} k * @return {number} */ export function countPairs(nums, k) { };`

### Example

**Input:** nums = [3,1,2,2,2,1,3], k = 2

**Output:** 4

**Explanation:**

There are 4 pairs that meet all the requirements:

- nums[0] == nums[6], and 0 * 6 == 0, which is divisible by 2.
- nums[2] == nums[3], and 2 * 3 == 6, which is divisible by 2.
- nums[2] == nums[4], and 2 * 4 == 8, which is divisible by 2.
- nums[3] == nums[4], and 3 * 4 == 12, which is divisible by 2.

**Input:** nums = [1,2,3,4], k = 1

**Output:** 0

**Explanation:** Since no value in nums is repeated, there are no pairs (i,j) that meet all the requirements.

**Constraints:**

`1 <= nums.length <= 100`

`1 <= nums[i], k <= 100`

Complete the given function and make sure that it passes the given test cases.