104 - Maximum Depth of Binary Tree

Details

Key	Value
Link	https://leetcode.com/problems/maximum-depth-of-binary-tree/
Language	Python 3
Runtime	55 ms, faster than 71.41% of Python3 online submissions for Maximum Depth of Binary Tree
Memory Usage	16.6 MB, less than 23.50% of Python3 online submissions for Maximum Depth of Binary Tree
Datastructures	TreeNode
Algorithms	DFS
Complexity	Time: O(N) Memory: O(logN)

Procedure

1. ...

Code

Option 1: Terse

# 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
        return max(self.maxDepth(root.left), self.maxDepth(root.right)) + 1

Option 2: Verbose

# 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:
        depth = 1
        def dfs(node):
            nonlocal depth
            if not node: return 0
            if not node.left and not node.right: return 0
            depth += 1
            dfs(node.left)
            dfs(node.right)
        
        dfs(root)
        return depth