# Merge Two Sorted Lists

> LeetCode #21 — Merge Two Sorted Lists. Solve on LeetCode, then implement here if you want it in your drill queue.

https://leetcode.com/problems/merge-two-sorted-lists/

Canonical: https://learn.significanthobbies.com/curriculum/drills/lc-merge-two-sorted-lists

LeetCode #21 — Merge Two Sorted Lists. Solve on LeetCode, then implement here if you want it in your drill queue.

https://leetcode.com/problems/merge-two-sorted-lists/

## The mechanism

A linked list trades fast random access for fast inserts and deletes wherever you already have a pointer. The classic moves: a dummy head to simplify edge cases, two pointers (fast and slow), and reversing in place.

## Expected evidence

Pass all LeetCode test cases for this problem.

## Hints

- Pattern hint: linked list.
- Start with brute force, then optimize time/space.
- Write down invariants before coding.

## Sources and practice

- [VisuAlgo — Linked List](https://visualgo.net/en/list)
- [Study Linked List](https://learn.significanthobbies.com/curriculum/concepts/linked-list)
- [Try the interactive drill](https://learn.significanthobbies.com/drills/lc-merge-two-sorted-lists)
- [All practice briefs](https://learn.significanthobbies.com/curriculum/drills/)