- Given the
rootof 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.
- This challenge corresponds to LeetCode #104.
- The number of nodes in the tree is in the range
-100 <= Node.val <= 100
root = [3, 9, 20, null, null, 15, 7]
root = [1, null, 2]
Below is my solution and some test cases. This solution has a linear time complexity O(n) and a linear space complexity O(n), where n is the length of the input list.