104. Maximum Depth of Binary Tree
- Total Accepted: 184446
- Total Submissions: 369369
- Difficulty: Easy
- Contributors: Admin
Given a binary tree, find its maximum depth.
The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.
Code (BFS)
from collections import *
# Definition for a binary tree node.
# class TreeNode(object):
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None
class Solution(object):
def maxDepth(self, root):
"""
:type root: TreeNode
:rtype: int
"""
if root is None:
return 0
q = deque([(root, 1)])
max_lvl = 1
while q:
node, lvl = q.popleft()
max_lvl = max(max_lvl, lvl)
if node.left is not None:
q.append((node.left, lvl+1))
if node.right is not None:
q.append((node.right, lvl+1))
return max_lvl
Code (DFS)
from collections import *
# Definition for a binary tree node.
# class TreeNode(object):
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None
class Solution(object):
def maxDepth(self, root):
"""
:type root: TreeNode
:rtype: int
"""
return max(self.maxDepth(root.left), self.maxDepth(root.right))+1 if root is not None else 0