Here’s a practical breakdown of Linked List patterns actually asked in FAANG interviews, grouped by technique:
1. Fast & Slow Pointers (Floyd’s Cycle)
Core pattern — detecting cycles, finding midpoints.
- 141. Linked List Cycle — basic detection
- 142. Linked List Cycle II — find the start of the cycle
- 876. Middle of the Linked List — classic warmup, often used as a subroutine
- 234. Palindrome Linked List — find middle + reverse second half + compare
2. Reversal
Manipulating pointers in place — extremely common, tests pointer discipline.
- 206. Reverse Linked List — the foundational one, know it cold (iterative + recursive)
- 92. Reverse Linked List II — reverse a sub-range (m to n)
- 25. Reverse Nodes in k-Group — hard, but asked a lot at Google/Meta — combines reversal + recursion/iteration in chunks
- 24. Swap Nodes in Pairs — special case of k-group with k=2
3. Merge / Two-Pointer Traversal
- 21. Merge Two Sorted Lists — extremely common, also a building block for merge sort on lists
- 23. Merge k Sorted Lists — heap-based or divide & conquer, very frequently asked at Amazon/Google
- 148. Sort List — merge sort on linked list, O(n log n) with O(1) space expected
4. Dummy Node / Removal Patterns
- 19. Remove Nth Node From End of List — two-pointer with gap, classic
- 83. Remove Duplicates from Sorted List — easy warmup
- 82. Remove Duplicates from Sorted List II — remove all nodes with duplicates, needs dummy node
- 203. Remove Linked List Elements — basic dummy-node deletion
5. Intersection / Structural Comparison
- 160. Intersection of Two Linked Lists — two-pointer switch-trick, very common, tests clean thinking over brute force
- 2130. Maximum Twin Sum of a Linked List — combo of middle-finding + reversal, been showing up more recently (Meta/Amazon)
6. Arithmetic on Lists (simulate math with nodes)
- 2. Add Two Numbers — digit-by-digit addition with carry, very frequently asked
- 445. Add Two Numbers II — same but numbers are in forward order, forces you to use a stack or reverse first
7. Copy / Deep Clone with Extra Pointers
- 138. Copy List with Random Pointer — hashmap or interweaving trick, asked a lot at Amazon/Meta, tests handling of non-trivial pointer structures
8. Design (Linked List as building block)
- 146. LRU Cache — doubly linked list + hashmap, this is asked constantly (probably top-3 most asked linked-list-adjacent question overall)
- 707. Design Linked List — less common now, but occasionally used to check fundamentals
If you only have time for a subset, prioritize in this order: 206, 21, 141/142, 19, 2, 23, 138, 146, 25, 92. These cover every core pattern and show up across Google/Meta/Amazon rotations repeatedly, whereas things like 707 or niche variations rarely appear anymore.
Want me to pull a similar breakdown for another topic (Trees, Sliding Window, etc.) or turn this into a study tracker?