Sort List (Merge Sort on Linked Lists)

Divide and Conquer / Slow & Fast PointersSolved Nov 22, 2025

Solve on LeetCode↗

Watch walkthrough View notes on GitHub

Walkthroughbest after you try it

NeetCodeOpen on YouTube ↗

Brute forceO(N²)

OptimizedO(N log N)

SpaceO(log N) due to recursion stack

Learn the concept

Watch: Linked Lists: Singly & Doubly Linked · Greg Hogg · 2024

AlgoChronicle

Beginner DSA path for visitors · journal by Srujan Chidarla.

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Watch: 10 Sorting Algorithms Easily Explained · Coding with Lewis · 2024

Asked in interviews at

4 in the last 6 months

Amazon
Bloomberg
Google
Meta
Lyft
ByteDance
Microsoft
Oracle
TikTok

Community-reported company tags from leetcode-company-wise-problems (updated 2026-10-08). Bar shows how often each company asks it.

Problem

Problem Description

Given the head of a linked list, return the list after sorting it in ascending order. The solution should run in O(n log n) time and using constant extra space (excluding the recursion stack).

Solve it yourself before you look

Reading the solution first feels like progress, but it makes the next similar problem — and the interview version — much harder, because you skipped the part where you figure it out. Give it an honest 20–30 minutes. Stuck? Re-read the pattern, watch the concept video, or try the brute force first.

Hidden: approach · solution code

#linked-list#sorting#merge-sort#two-pointers

Revising this one?

→Solve it from memory before peeking
→Say the pattern out loud, not just the code
→Explain it like you would to a friend
→Try it again in a different language

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