Leetcode: Maximum Depth of N-ary Tree

Today we're going to solve one Leetcode: Maximum Depth of N-ary Tree.
It's an easy question, as well as the solution is. This question is related to the tree structure. We are going to use a recursive function with O(n) complexity whereas n is equal to the count of nodes in the tree.
Projects:
Symptom Diary: symptom-diary.com
Pet 4 Pet: pet-4-pet.com
C#, .net, .net core, leet code, algorithmic problem, b-tree, tree, tree traversing, tree structure, maximum depth, DFS, depth first search