Given an integer array arr of size N and an integer k, return the number of good subarrays of arr.
A good array is an array where the number of different integers in that is exactly k.
For example, {1, 3, 4, 4, 1} has 3 different integers: 1, 3, and 4.
Note : A subarray is a contiguous part of an array.
Example 1:
Input:
N = 5
k = 2
arr[ ] = {1, 2, 1, 2, 3}
Output: 7
Explanation: Subarrays formed with exactly 2 different integers: {1, 2}, {2, 1}, {1, 2}, {2, 3}, {1, 2, 1}, {2, 1, 2}, {1, 2, 1, 2}.

Example 2:
Input:
N = 5
k = 3
arr[ ] = {1, 2, 1, 3, 4}
Output: 3

Your Task:
You don't need to read input or print anything. Your task is to complete the function subarrayCount() which takes the array of integers arr , an integer N and k as parameters and returns a number of good subarrays.
Expected Time Complexity: O(N)
Expected Auxiliary Space: O(N)
Constraints:
1 ≤ N ≤ 10^{5}
1 ≤ k ≤ N
^{1 }≤ arr_{i }≤ N

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