https://practice.geeksforgeeks.org/problems/array-pair-sum-divisibility-problem3257/1
Given an array of integers and a number k, write a function that returns true if given array can be divided into pairs such that sum of every pair is divisible by k.
Example 1 :
Input : arr = [9, 5, 7, 3], k = 6 Output: True Explanation: {(9, 3), (5, 7)} is a possible solution. 9 + 3 = 12 is divisible by 6 and 7 + 5 = 12 is also divisible by 6.
Example 2:
Input : arr = [2, 4, 1, 3], k = 4 Output: False Explanation: There is no possible solution.
Your Task: You don't need to read or print anything. Your task is to complete the function canPair() which takes array and k as input parameter and returns true if array can be divided into pairs such that sum of every pair is divisible by k otherwise returns false.
Expected Time Complexity: O(n) Expected Space Complexity : O(n)
Constraints: 1 <= length of array <= 100000 1 <= elements of array <= 100000 1 <= k <= 100000