589. N-ary Tree Preorder Traversal
Easy
10 Points
Stack
Tree
Depth-First Search
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)
Examples
Example 1
Input: root = [1,null,3,2,4,null,5,6]
Output: [1,3,5,6,2,4]
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: [1,2,3,6,7,11,14,4,8,12,5,9,13,10]
Constraints
The number of nodes in the tree is in the range [0, 104].0 <= Node.val <= 104The height of the n-ary tree is less than or equal to 1000.
Follow Up
- Recursive solution is trivial, could you do it iteratively?
589. N-ary Tree Preorder Traversal
Easy
10 Points
Stack
Tree
Depth-First Search
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)
Examples
Example 1
Input: root = [1,null,3,2,4,null,5,6]
Output: [1,3,5,6,2,4]
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: [1,2,3,6,7,11,14,4,8,12,5,9,13,10]
Constraints
The number of nodes in the tree is in the range [0, 104].0 <= Node.val <= 104The height of the n-ary tree is less than or equal to 1000.
Follow Up
- Recursive solution is trivial, could you do it iteratively?