Key Patterns to Master
- Fast & Slow Pointers: For cycle detection and finding the middle.
- Sentinel Nodes: For simplifying head/tail edge cases.
- In-Place Reversal: For reversing segments of the list.
Hand-Picked Problems
| Problem | Difficulty | Key Pattern |
|---|---|---|
| Linked List Cycle | Easy | Fast/Slow |
| Reverse Linked List | Easy | In-place |
| Merge Two Sorted Lists | Easy | Sentinel Node |
| Remove Nth Node From End | Medium | Length/Two Pointers |
| Palindrome Linked List | Easy | Reversal + Middle |
| Copy List with Random Pointer | Medium | HashMap |
| Linked List Cycle II | Medium | Cycle Entry |
| Intersection of Two Lists | Easy | Length Diff |
| Reverse Nodes in k-Group | Hard | Advanced Reversal |
| LRU Cache | Medium | Doubly Linked List |
Interview Tip
Always ask: "Is it a singly or doubly linked list?" and "Can the values be negative?"