Python3实现二叉树的最大深度

# Definition for a binary tree node.
# class TreeNode:
#   def __init__(self, x):
#     self.val = x
#     self.left = None
#     self.right = None

class Solution:
  def maxDepth(self, root: TreeNode) -> int:
    if root==None:
      return 0
    count = self.getDepth(root,0)
    return count
  
  def getDepth(self,node,count):
    if node!=None:
      num1 = self.getDepth(node.left,count+1);
      num2 = self.getDepth(node.right,count+1);
      num = num1 if num1>num2 else num2
      return num
    else:
      return count