2176\. Count Equal and Divisible Pairs in an Array

Easy

Given a **0-indexed** integer array `nums` of length `n` and an integer `k`, 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`.

**Example 1:**

**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. 

**Example 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`
