0429. N ary Tree Level Order Traversal - kumaeki/LeetCode GitHub Wiki
0429. N-ary Tree Level Order Traversal
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, 10^4]
链表.
/*
// 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>> result = new ArrayList<>();
if(root == null)
return result;
ArrayDeque<Node> que = new ArrayDeque<>();
que.addLast(root);
while(que.size() > 0){
List<Integer> list = new ArrayList<>();
int size = que.size();
while(size-- > 0){
Node node = que.removeFirst();
list.add(node.val);
node.children.forEach(c -> que.addLast(c));
}
result.add(list);
}
return result;
}
}