标签：present traversal child link poll ati root values pre
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]]
/* // Definition for a Node. class Node { public int val; public List<Node> children; public Node() {} public Node(int _val) { val = _val; } public Node(int _val, List<Node> _children) { val = _val; children = _children; } }; */ class Solution { public List<List<Integer>> levelOrder(Node root) { List<List<Integer>> res = new ArrayList<>(); if (root == null) { return res; } Queue<Node> queue = new LinkedList<>(); queue.offer(root); while (!queue.isEmpty()) { int size = queue.size(); List<Integer> list = new ArrayList<>(); for (int i = 0; i < size; i++) { Node cur = queue.poll(); list.add(cur.val); for (Node node: cur.children) { if (node != null) { queue.offer(node); } } } res.add(list); } return res; } }
[LC] 429. N-ary Tree Level Order Traversal
标签：present traversal child link poll ati root values pre
原文地址：https://www.cnblogs.com/xuanlu/p/12148716.html
