题目链接

层序遍历

java">/*
// 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>> list = new ArrayList();LinkedList<Node> queue = new LinkedList<>();if(root != null){queue.offer(root);}while(!queue.isEmpty()){List<Integer> list1 = new ArrayList();int size = queue.size();for(int i = 0; i < size; i++){Node node = queue.poll();// 与二叉树相比变化代码list1.add(node.val);if(node.children != null){queue.addAll(node.children);}}list.add(list1);}return list;}
}