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}