0104 Maximum Depth of Binary Tree

Solved at: 2023-01-29

Question

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.

Solution

swift

class Solution {    func maxDepth(_ root: TreeNode?) -> Int {        guard root != nil else {return 0}        return max(maxDepth(root!.right), maxDepth(root!.left)) + 1    }}

class Solution {    func maxDepth(_ root: TreeNode?) -> Int {        guard root != nil else {return 0}        return max(maxDepth(root!.right), maxDepth(root!.left)) + 1    }}

Results

Runtime 26 ms Beats 73.36%
Memory 14.7 MB Beats 58.61%

Complexity Analysis

Time: $O(N)$
Space: $O(N)$

Takeaways

We can also use BFS to traverse the tree