Combinations Problem IV

Given an integer array, find all distinct combinations of a given length `k`, where the repetition of elements is allowed.

Input : [1, 2, 3], k = 2
Output: {[1, 1], [1, 2], [1, 3], [2, 2], [2, 3], [3, 3]}

Input : [1, 1, 1], k = 2
Output: {[1, 1]}

Input : [1, 2], k = 0
Output: {[]}

Input : [], k = 1
Output: {}

The solution should consider only distinct combinations. For example, either [1, 1, 2] or [1, 2, 1] or [2, 1, 1] should be considered for the below input. Same goes for [1, 2, 2] or [2, 1, 2] or [2, 2, 1].

Input : [1, 2, 1], k = 3
Output: {[1, 1, 1], [1, 1, 2], [1, 2, 2], [2, 2, 2]}

Practice link: https://www.techiedelight.com/?problem=CombinationsIV