00104_maximum_depth_of_binary_tree

Maximum Depth of Binary Tree

Link to Problem: https://leetcode.com/problems/maximum-depth-of-binary-tree

Description

Given the root of a binary tree, return its maximum depth.

A binary tree's maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.

Examples

Example 1

graph
  A((3)) --> B((9))
  A --> C((20))
  C --> D((15))
  C --> E((7))

Loading

Input: root = [3,9,20,null,null,15,7]
Output: 3

Example 2

Input: root = [1,null,2]
Output: 2

Thoughts

I feel defeated by this problem. While I understand the algorithm, I wouldn't have figured out how to write the solution in Elixir on my own.

I guess it makes sense because even though I'm starting to get the hang of recursion, the way I've used recursion so far is to return the node itself and not a regular value. This meant that I'm used to writing the functions where the argument is usually just itself.

Hopefully I get the hang of this in the future.