from collections import deque
# Definition for a binary tree node.
# class TreeNode:
# def __init__(self, val=0, left=None, right=None):
# self.val = val
# self.left = left
# self.right = right
class Solution:
def maxDepth(self, root: Optional[TreeNode]) -> int:
if not root:
return 0
def dfs(node, depth):
if not node:
return depth - 1
return max(dfs(node.left, depth + 1), dfs(node.right, depth + 1))
return dfs(root, 1)
from collections import deque
# Definition for a binary tree node.
# class TreeNode:
# def __init__(self, val=0, left=None, right=None):
# self.val = val
# self.left = left
# self.right = right
class Solution:
def maxDepth(self, root: Optional[TreeNode]) -> int:
if root is None:
return 0;
cnt = 0
q = deque([root])
while q:
for i in range(len(q)):
u = q.popleft()
if u.left:
q.append(u.left)
if u.right:
q.append(u.right)
cnt += 1
return cnt