Permutations Problem Statement

Given an array of distinct integers, generate and return all the possible permutations of the array.

Example:

Input:

ARR = [1, 2]

Output:

[[1, 2], [2, 1]]

Explanation:

The array has 2 elements, thus has 2! = 2 permutations. The permutations are the array itself, [1, 2], and [2, 1], where the elements are swapped.

Constraints:

• 1 <= T <= 10
• 1 <= N <= 7
• -10^9 <= ARR[i] <= 10^9

Note:

• All the numbers in the array are unique.
• You can return the permutations in any order.
• The original array is considered a valid permutation of itself.