N-ary Tree Level Order Traversal - LeetCode
Given an n-ary tree, return the level order traversal of its nodes' values. 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: [[1],[3,2,4],[5,6]]
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: [[1],[2,3,4,5],[6,7,8,9,10],[11,12,13],[14]]
Constraints:
The height of the n-ary tree is less than or equal to 1000 The total number of nodes is between [0, 104]
- code
class Solution:
def levelOrder(self, root: 'Node') -> List[List[int]]:
if not root: return []
res = []
level = [root]
while level:
res.append([i.val for i in level])
nex = [i for node in level for i in node.children if i]
level = nex
return res