Check If Array Pairs Are Divisible by k
Given an array of integers arr of even length n and an integer k.
We want to divide the array into exactly n / 2 pairs such that the sum of each pair is divisible by k.
Return true if you can find a way to do that, or false otherwise.
Example 1
Input
arr = [1,2,3,4,5,10,6,7,8,9], k = 5Output
truePairs are (1,9), (2,8), (3,7), (4,6), and (5,10).
Example 2
Input
arr = [1,2,3,4,5,6], k = 7Output
truePairs are (1,6), (2,5), and (3,4).
Constraints
- arr.length == n
- 1 <= n <= 10^5
- n is even.
- -10^9 <= arr[i] <= 10^9
- 1 <= k <= 10^5