559. Maximum Depth of N-ary Tree

Easy

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.

Solution

class Solution:
    def maxDepth(self, root: "Node") -> int:
        if root is None:
            return 0

        return self.helper(root, 1)

    def helper(self, root: "Node", depth: int) -> int:
        if len(root.children) == 0:
            return depth

        return max([self.helper(child, depth + 1) for child in root.children])


class Node:
    def __init__(self, val=None, children=None):
        self.val = val
        self.children = children