Transform matrix to sorted array
Last updated: November 26, 2025
Quick Overview
Given a 2D matrix of integers, transform it into a sorted 1D array in ascending order. The matrix may contain duplicate values, and the output should be a single array containing all the elements from the matrix, sorted from the smallest to the largest. The function should return this sorted array as the output.
Grubhub
November 26, 20256
6
4,155 solved
Given a 2D matrix of integers, transform it into a sorted 1D array in ascending order. The matrix may contain duplicate values, and the output should be a single array containing all the elements from the matrix, sorted from the smallest to the largest. The function should return this sorted array as the output.
This coding problem is frequently asked during Technical Screen at Grubhub. The interviewer is testing your ability to translate a problem into clean, working code while discussing time and space complexity. Grubhub expects candidates to write production-quality code, not just solve the puzzle.
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
- Can you solve this iteratively instead of recursively (or vice versa)?
- How would you test this solution thoroughly?
- Can you solve this in a single pass?
Sharpen Your Skills on Codemia
Practice similar problems with our interactive workspace, get AI feedback, and track your progress.
Practice DSA ProblemsSample Answer
Problem Analysis
To transform a 2D matrix of integers into a sorted 1D array, we can recognize that this problem doesn’t require complex algorithms like BFS or dynamic programming. Instead, it can be approached using ...
Approach
-
Flatten the Matrix: Loop through each element of the 2D matrix and add it to a 1D list. For example, given the matrix:
[[3, 1, 2], [5, 4, 6]],
the flattened list will be [3, 1...
Submit Your Answer
