Given a root of an N-ary tree, return a deep copy (clone) of the tree. Each node in the n-ary tree contains a val (int) and a list (List[Node]) of its children. class Node { public int val; public List<Node> children; } Nary-Tree input serialization is represented in their level order traversal, each group of children is separated by the null value (See examples). Follow up: Can your solution work for the graph problem? Example 1: Input: root = [1,null,3,2,4,null,5,6] Output: [1,null,3,2,4,null,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,null,2,3,4,5,null,null,6,7,null,8,null,9,10,null,null,11,null,12,null,13,null,null,14] Constraints: The depth of the n-ary tree is less than or equal to 1000. The total number of nodes is between [0, 10^4].