思路：简单的n-tree 遍历


代码：
/*
// Definition for a Node.
class Node {
    public int val;
    public List<Node> children;

    
    public Node() {
        children = new ArrayList<Node>();
    }
    
    public Node(int _val) {
        val = _val;
        children = new ArrayList<Node>();
    }
    
    public Node(int _val,ArrayList<Node> _children) {
        val = _val;
        children = _children;
    }
};
*/

class Solution {
    Map<Node,Node>map=new HashMap<>();
    public Node cloneTree(Node root) {
        if(root==null)return null;
        Node R=new Node(root.val);
        dfs(root,R);
        return R;
    }


    public void dfs(Node root,Node R){
        if(root==null)return;

        List<Node>childs=root.children;

        for(Node c:childs){
            Node node=new Node(c.val);
            R.children.add(node);
            dfs(c,node);
        }
    }
}