543 Diameter of Binary Tree | Beginner friendly W/ Thinking Process

LeetCode 543 Diameter of Binary Tree

**What you can learn**:
1. Using DFS to traverse a tree

**Why beginner friendly**:
There's no rehearsal or any outline while solving this problem. Therefore, you may find I will be stuck at some point and see how figure it out in another way. I am trying to show you when I am encountering a "brand new problem", what I am thinking and what kind of data structure and technique I will use I learnt before (Of course, I have done these problems before a long time ago which also means forget most of the details.)
Feel free to let me know if you have any questions, a better solution or what I can improve. Thanks for your watching.

#leetcode #leetcodeing #algorithm #algorithms #datastructure #tree #binarytree #bfs #breadthfirstsearch #dfs #depthfirstsearch