maximum_depth_of_binary_tree 

 1from utils import TreeNode
 2from typing import Optional
 3
 4
 5# @leet start
 6class Solution:
 7    def maxDepth(self, root: Optional[TreeNode], depth: int = 0) -> int:
 8        """
 9        To find the maximum depth of a tree, we can divide it into subproblems.
10        1. If the root is null, the depth is 0.
11        2. If the root is non-null, the depth is the maximum of the left and right
12        sutbrees + 1.
13        We apply that rule throughout the tree to get the depth.
14        """
15        if not root:
16            return depth
17        return 1 + max(self.maxDepth(root.left), self.maxDepth(root.right))
18
19
20# @leet end
21
22
23def test():
24    assert 2 + 2 == 4
class Solution: 
 7class Solution:
 8    def maxDepth(self, root: Optional[TreeNode], depth: int = 0) -> int:
 9        """
10        To find the maximum depth of a tree, we can divide it into subproblems.
11        1. If the root is null, the depth is 0.
12        2. If the root is non-null, the depth is the maximum of the left and right
13        sutbrees + 1.
14        We apply that rule throughout the tree to get the depth.
15        """
16        if not root:
17            return depth
18        return 1 + max(self.maxDepth(root.left), self.maxDepth(root.right))
def maxDepth(self, root: Optional[utils.TreeNode], depth: int = 0) -> int: 
 8    def maxDepth(self, root: Optional[TreeNode], depth: int = 0) -> int:
 9        """
10        To find the maximum depth of a tree, we can divide it into subproblems.
11        1. If the root is null, the depth is 0.
12        2. If the root is non-null, the depth is the maximum of the left and right
13        sutbrees + 1.
14        We apply that rule throughout the tree to get the depth.
15        """
16        if not root:
17            return depth
18        return 1 + max(self.maxDepth(root.left), self.maxDepth(root.right))

To find the maximum depth of a tree, we can divide it into subproblems.

  1. If the root is null, the depth is 0.
  2. If the root is non-null, the depth is the maximum of the left and right sutbrees + 1. We apply that rule throughout the tree to get the depth.
def test(): 
24def test():
25    assert 2 + 2 == 4