You are given two integer arrays, arr1 and arr2. Your task is to return a new array containing the intersection of both arrays.

• Each element in the result must be unique.

• The order of the elements in the result does not matter.

Constraints

• $1 \leq$ arr1.length, arr2.length $\leq 1000$

• $0 \leq$arr1[i], arr2[i] $\leq 1000$

The essence of this solution lies in using a hash map to efficiently find the unique intersection of two arrays. A naive approach would be to compare every element of the first array with every element of the second, which results in a time complexity of $O(n·m)$ ...