0104-maximum-depth-of-binary-tree¶
Try it on leetcode
Description¶
Given the root of a binary tree, return its maximum depth.
A binary tree's maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.
Example 1:
Input: root = [3,9,20,null,null,15,7] Output: 3
Example 2:
Input: root = [1,null,2] Output: 2
Constraints:
- The number of nodes in the tree is in the range
[0, 104]. -100 <= Node.val <= 100
Solution(Python)¶
# 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: TreeNode | None) -> int:
if not root:
return 0
queue = deque([root])
depth = 0
while queue:
for _ in range(len(queue)):
curr = queue.popleft()
if curr.left:
queue.append(curr.left)
if curr.right:
queue.append(curr.right)
depth += 1
return depth