2025-07-30 15:45:39 +0000 UTC

N-ary Tree Preorder Traversal

Code

"""
# Definition for a Node.
class Node:
    def __init__(self, val: Optional[int] = None, children: Optional[List['Node']] = None):
        self.val = val
        self.children = children
"""

class Solution:
    def preorder(self, root: 'Node') -> List[int]:
        if root is None:
            return []
        res = []
        queue = [root]
        while queue:
            node = queue.pop()
            res.append(node.val)
            queue.extend(reversed(node.children))
        return res