Trees · Coding problem
Binary Tree Inorder 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 inorder traversal (left, node, right).
Input format (this platform's convention, not LeetCode's)
The tree is given as a flat, 0-indexed array where the node at index i has its left child at index 2*i + 1 and its right child at index 2*i + 2. The literal token null marks a missing node.
Example
Input: [1, 2, 3, 4, 5, 6, 7]
Output: 4 2 5 1 6 3 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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