1497 - Check If Array Pairs Are Divisible by k.

Medium

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 = 5

Output: true

Explanation: Pairs are (1,9),(2,8),(3,7),(4,6) and (5,10).

Example 2:

Input: arr = 1,2,3,4,5,6, k = 7

Output: true

Explanation: Pairs are (1,6),(2,5) and(3,4).

Example 3:

Input: arr = 1,2,3,4,5,6, k = 10

Output: false

Explanation: You can try all possible pairs to see that there is no way to divide arr into 3 pairs each with sum divisible by 10.

Constraints:

• arr.length == n

• <code>1 <= n <= 10⁵</code>

• n is even.

• <code>-10⁹<= arri<= 10⁹</code>

• <code>1 <= k <= 10⁵</code>