Trees · Coding problem
Binary Tree Preorder Traversal
A free coding problem from the Binary Tree DFS Traversal Orders skill. Read it here, then solve it in the app in Java or Python.
- Easy
- Coding problem
- Free
- Java and Python
The problem
Given the root of a binary tree, return its preorder traversal (node, left, right).
Example
Input: [1, 2, 3, 4, 5, 6, 7]
Output: 1 2 4 5 3 6 7
Constraints
0 <= number of array tokens <= 2000-10^4 <= node value <= 10^4
How it's graded
- Run checks your code against the examples. Submit also runs a hidden suite in four groups - basic cases, edge cases, random inputs and performance tests at the size limit - and shows which groups pass, never the hidden inputs.
- Stuck? Hints come in four steps, from a nudge to a code skeleton, each costing part of the points.
- Once you pass, you see the approaches from brute force to optimal, and where your solution lands among them.
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