0104 Maximum Depth of Binary Tree

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Solved at: 230129

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

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

Coding Tests