/*
// 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) {
//建立结果数组
List<List<Integer>> ans = new ArrayList<>();
while(root == null){
return ans;
}
//建立队列
Queue<Node> q = new LinkedList<>();
//根节点入队列
q.add(root);
while(!q.isEmpty()){
List<Integer> tem = new ArrayList<>();
int size = q.size();
for(int i = 0;i < size;i++){
Node cur = q.poll();
if(cur == null) continue;
tem.add(cur.val);
//建立孩子列表
List<Node> children = cur.children;
for(Node child : children){
if(child != null){
q.add(child);
}
}
}
ans.add(tem);
}
return ans;
}
}
