Merge K Sorted linked lists
Last updated: October 8, 2025
Quick Overview
Given K sorted linked lists, merge them into a single sorted linked list. The input consists of an array of linked list heads, and the output should be the head of the newly merged sorted linked list. Ensure that the solution efficiently handles the merging process, aiming for optimal time complexity.
Netflix
October 8, 202537
7
2,825 solved
Given K sorted linked lists, merge them into a single sorted linked list. The input consists of an array of linked list heads, and the output should be the head of the newly merged sorted linked list. Ensure that the solution efficiently handles the merging process, aiming for optimal time complexity.
Coding interviews at Netflix 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
- Quickly identify the optimal approach and its theoretical basis
- Handle complex algorithm design with multiple interacting components
- Write concise, elegant code under time pressure
- Prove correctness of your approach and discuss alternative solutions
- Optimize beyond the obvious: discuss constant factor improvements
- Address follow-up variations and explain how the solution generalizes
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 in a single pass?
- How would you modify your solution to handle streaming input?
- What if the input doesn't fit in memory?
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 merge K sorted linked lists efficiently, we can employ a min-heap (or priority queue) approach. This technique allows us to always access the smallest element among the heads of the K lists, en...
Approach
- Initialize a min-heap and insert the head of each of the K linked lists into it.
- Create a dummy node to help build the merged list. Use a pointer to track the last node added to the me...
Submit Your Answer
