104-Maximum-Depth-of-Binary-Tree.py

class Solution:
    def maxDepth(self, root: Optional[TreeNode]) -> int:
        if not root:
            return 0
        else:
            lDepth = self.maxDepth(root.left)
            rDepth = self.maxDepth(root.right)
            return max(lDepth, rDepth) + 1