Merge k Sorted Lists: which companies ask it and how to practise

Merge k Sorted Lists is a Hard problem that 49 companies are reported to ask. This page shows who, how often and how recently, what the question tests, and how to practise it out loud with an interviewer who asks follow-ups. We link to the original problem statement instead of copying it.

Which companies ask Merge k Sorted Lists?

Public company lists attribute Merge k Sorted Lists, a Hard problem, to 49 companies. The most frequent askers are Deloitte, Netskope and X. 11 reports are from the last six months. It mainly tests linked list, divide and conquer and heap (priority queue). Use this as a practice guide, not a promise.

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Who asks Merge k Sorted Lists

49 companies appear in the public lists for this question. By how often each is reported: Deloitte (very often), Netskope (very often), X (very often), FreshWorks (very often), IXL (very often), Cohesity (very often), oyo (very often), Disney (very often), MongoDB (very often) and Rivian (very often), and 39 more. 11 of them were reported in the last six months, Deloitte, FreshWorks and Nvidia among them.

These are candidate reports collected in public lists, not statements from the companies. They are a good guide to what to practise and a poor guide to what you will be asked: interviewers change questions, and the same company asks different questions by team and level. Last reviewed 25 October 2026.

What Merge k Sorted Lists tests

It is rated Hard, so a correct brute force with a clear path to the better idea is a good result; interviewers watch how you reason when the answer is not obvious and how you use their hints.

Linked lists test pointer discipline: what you save before you overwrite a link, the head and tail edge cases, and whether a dummy node simplifies the code.

Divide and conquer splits the input, solves the halves, and merges. The cost is in the merge step, so say what it is.

A heap gives the smallest or largest item in logarithmic time. It is the usual answer to the k largest, the running median, or merging sorted streams.

How to practise it

Do not just solve it silently. In a real interview you explain the approach before you code, write while you talk, and defend the solution to follow-ups. Set a timer, say the brute force and its cost first, then improve it, and finish by stating the time and space complexity and two edge cases you tested.

On giveinterview you can take this kind of question as a spoken interview: the AI interviewer opens with the problem, watches you code, asks cross-questions and ends with a scorecard. Your first 3 single-question interviews are free for life, every interview report is free, and a new account also gets 6 welcome credits.

Read the original statement here: https://leetcode.com/problems/merge-k-sorted-lists/ (opens the publisher's page). The statement is theirs; we do not reproduce it.

Questions to practise next

If you can solve Merge k Sorted Lists, try these next, chosen because they share its main topic and many of the same companies: LRU Cache (Medium), Merge Two Sorted Lists (Easy), Add Two Numbers (Medium), Reverse Linked List (Easy), LFU Cache (Hard) and Reverse Nodes in k-Group (Hard). Each has its own page in the questions list.

Frequently asked questions

Is Merge k Sorted Lists asked at Amazon?

Amazon appears in the public lists for Merge k Sorted Lists, reported often. Treat that as a reason to practise it, not a promise you will be asked it.

How hard is Merge k Sorted Lists?