Given a matrix of characters, return True if the word is contained within the matrix by visiting horizontally and vertically adjacent fields.
Given two integers n and k, create all possible solutions with all numbers from [1,n] of k length.
Create an implementation of a Trie structure.
Given an array nums and a number k, return true if there are two distinct indices i and j in the array such that nums[i] == nums[j] and abs(i - j) <= k.