Introduction

In this blog post, we will explore how to solve the LeetCode problem "559" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

Given a n-ary 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. Nary-Tree input serialization is represented in their level order traversal, each group of children is separated by the null value (See examples). Example 1: Input: root = [1,null,3,2,4,null,5,6] Output: 3 Example 2: Input: root = [1,null,2,3,4,5,null,null,6,7,null,8,null,9,10,null,null,11,null,12,null,13,null,null,14] Output: 5 Constraints: The total number of nodes is in the range [0, 104]. The depth of the n-ary tree is less than or equal to 1000.

Explanation

Here's an efficient solution to find the maximum depth of an n-ary tree, along with explanations and complexity analysis:

• High-Level Approach:

  • Perform a Depth-First Search (DFS) traversal of the tree.
  • Recursively calculate the depth of each node. The depth of a node is 1 plus the maximum depth of its children.
  • Return 0 if the root is None, indicating an empty tree.

• Complexity Analysis:

  • Runtime Complexity: O(N), where N is the number of nodes in the tree. We visit each node once.
  • Storage Complexity: O(H), where H is the height of the tree. This is due to the recursive call stack in DFS. In the worst case (skewed tree), H can be N, but in a balanced tree, it's O(log N).

Code

    """
# Definition for a Node.
class Node:
    def __init__(self, val=None, children=None):
        self.val = val
        self.children = children
"""

class Solution:
    def maxDepth(self, root: 'Node') -> int:
        """
        Calculates the maximum depth of an N-ary tree.

        Args:
            root: The root node of the N-ary tree.

        Returns:
            The maximum depth of the tree.
        """
        if not root:
            return 0

        max_child_depth = 0
        if root.children:
            for child in root.children:
                max_child_depth = max(max_child_depth, self.maxDepth(child))

        return 1 + max_child_depth