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Given an array of **N** integers, and an integer **K**, find the number of pairs of elements in the array whose sum is equal to **K**.

**Example 1:**

**Input:
**N = 4, K = 6
arr[] = {1, 5, 7, 1}
**Output:** 2
**Explanation:**
arr[0] + arr[1] = 1 + 5 = 6
and arr[1] + arr[3] = 5 + 1 = 6.

**Example 2:**

**Input:
**N = 4, X = 2
arr[] = {1, 1, 1, 1}
**Output:** 6
**Explanation:**
Each 1 will produce sum 2 with any 1.

**Your Task:**

You don't need to read input or print anything. Your task is to complete the function **getPairsCount()** which takes **arr[],** **n** and **k **as input parameters and returns the number of pairs that have sum K.

**Expected Time Complexity:** O(N)

**Expected Auxiliary Space:** O(N)

**Constraints:**

1 <= N <= 10^{5}

1 <= K <= 10^{8}

1 <= Arr[i] <= 10^{6}

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Count pairs with given sum

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