Given the root of an n-ary tree, return the preorder 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)
Input: root = [1,null,3,2,4,null,5,6]
Output: [1,3,5,6,2,4]
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: [1,2,3,6,7,11,14,4,8,12,5,9,13,10]
The number of nodes in the tree is in the range [0, 104].
0 <= Node.val <= 104
The height of the n-ary tree is less than or equal to 1000.
Solutions (Click to expand)
A Preorder traversal of a Binary Tree involves traversing the tree in a root, left child, right child order. We can apply this to an N-ary tree by traversing the root and all its children in order from left to right.
We will do a normal DFS traversal of the tree where every node we visit will first get inserted into a list. All of the children in the List<Node> will be traversed from left to right.
