Binary Tree Preorder Traversal 🐚
Apr 3, 2022
Given the root of a binary tree, return the preorder traversal of its nodes' values.
Example 1:
Input: root = [1,null,2,3]
Output: [1,2,3]Example 2:
Input: root = []
Output: []Example 3:
Input: root = [1]
Output: [1]Constraints:
- The number of nodes in the tree is in the range
[0, 100]. -100 <= Node.val <= 100
Follow up: Recursive solution is trivial, could you do it iteratively?
Solution
Time complexity O(n)
Space Complexity O(h) where h is the max height of the tree
Time complexity O(n)
Space Complexity O(h) where h is the max height of the tree
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