Transform matrix to tree
Last updated: October 23, 2025
Quick Overview
Given a matrix representing a binary tree, where each element corresponds to a node's value and its position indicates the tree structure, transform the matrix into a binary tree. The output should be the root node of the constructed binary tree. Ensure that the tree adheres to the properties of a binary tree, with left and right children correctly assigned based on the matrix indices.
Airbnb
October 23, 202539
7
3,475 solved
Given a matrix representing a binary tree, where each element corresponds to a node's value and its position indicates the tree structure, transform the matrix into a binary tree. The output should be the root node of the constructed binary tree. Ensure that the tree adheres to the properties of a binary tree, with left and right children correctly assigned based on the matrix indices.
Coding interviews at Airbnb focus on problem-solving approach as much as the final solution. The interviewer wants to see you break down the problem, consider edge cases, and optimize iteratively. Communication throughout the process is key.
What the Interviewer Expects
- Recognize the underlying problem pattern (sliding window, two pointers, BFS/DFS, etc.)
- Discuss multiple approaches and trade-offs before coding
- Implement an optimal solution with clean, production-quality code
- Handle all edge cases including boundary conditions and invalid input
- Optimize both time and space complexity with clear justification
- Test your solution systematically with well-chosen examples
Key Topics to Cover
How to Approach This
- Clarify input constraints and edge cases before writing code.
- Walk through your approach verbally and confirm with the interviewer before coding.
- Start with a brute force solution, then optimize. Mention time and space complexity.
- Test your solution with examples, including edge cases like empty input or duplicates.
- Consider common patterns: sliding window, two pointers, hash map, BFS/DFS, dynamic programming.
Possible Follow-up Questions
- What if the input doesn't fit in memory?
- What is the worst-case input for your solution?
- How would your solution change if the input was sorted?
- How would you parallelize this solution?
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Practice DSA ProblemsSample Answer
Problem Analysis
The problem involves transforming a matrix representation of a binary tree into an actual binary tree structure. The matrix indicates the tree hierarchy through its indices: the root node is at positi...
Approach
- Define a TreeNode class: Create a class to represent each node in the binary tree with attributes for the value, left child, and right child.
- Recursive Function: Implement a recursive he...
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