source: https://leetcode.com/problems/combinations/description/ Combinations Table of ContentsCombinationsDescriptionExample 1:Example 2:Constraints:Solution Description Given two integers n and k, return all possible combinations of k numbers chosen from the range [1, n].You may return the answer in any order. Example 1: Input: n = 4, k = 2Output: [[1,2],[1,3],[1,4],[2,3],[2,4],[3,4]]Explanation: There are 4 choose 2 = 6 total combinations. Note ...