Merge Three Sorted matrixs

Last updated: August 17, 2025

Quick Overview

Given k sorted linked lists, merge them into a single sorted result.

Salesforce
Coding & Algorithms
Software Engineer
Salesforce
August 17, 2025
Software Engineer
Technical Screen
Coding & Algorithms
Medium

235

13

4,667 solved


Given k sorted linked lists, merge them into a single sorted result.

This coding problem is frequently asked during Technical Screen at Salesforce. The interviewer is testing your ability to translate a problem into clean, working code while discussing time and space complexity. Salesforce 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
Tree structures and recursion
Binary search and divide and conquer
Hash maps and frequency counting
Time and space complexity analysis
Dynamic programming and memoization
Sorting and searching
How to Approach This
  1. Clarify input constraints and edge cases before writing code.
  2. Walk through your approach verbally and confirm with the interviewer before coding.
  3. Start with a brute force solution, then optimize. Mention time and space complexity.
  4. Test your solution with examples, including edge cases like empty input or duplicates.
  5. Consider common patterns: sliding window, two pointers, hash map, BFS/DFS, dynamic programming.
Possible Follow-up Questions
  • How would you parallelize this solution?
  • Can you optimize the space complexity of your solution?
  • What if the input doesn't fit in memory?
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Sample Answer
Problem Analysis

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Brute Force Approach

Always start with the simplest correct solution, even if it's not optimal. This shows you can solve the problem and gives you a baseline to optimize f...


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