Binary Tree Preorder Traversal
You are given the root of a binary tree. Your task is to return the preorder traversal of the tree. In preorder traversal, visit the root node first, then recursively traverse the left subtree followed by the right subtree.
Examples
Input: root = [1,null,2,3]
Output: [1,2,3]
Explanation: The nodes are visited in Root → Left → Right order.
Input: root = [4,2,6,1,3,5,7]
Output: [4,2,1,3,6,5,7]
Explanation: The preorder traversal visits the root before its subtrees.
Input: root = []
Output: []
Explanation: The tree is empty.
Constraints
- 0 = Number of nodes = 105
- -10? = Node.data = 10?
Companies
Topics
Solution.cs C#JavaPythonC++Javascript
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