Linked Lists

Problem	Complexity	Key Pattern
Lru Cache	O(1) for both get and put	O(1) cache with eviction — "design LRU/LFU cache", bounded-memory
Merge Two Sorted	O(n + m)	Merge step of merge sort — combining two sorted sequences into one.
Reverse Linked List	O(n)	In-place linked list reversal — "reverse list", "reverse sublist",