Advanced data structures look intimidating until you connect each one to the operation it makes faster: prefix lookup, recency updates, range queries, or prefix sums.
Structure Map
| Data Structure | Optimizes | Practice |
|---|---|---|
| Trie | Prefix lookup | Implement Trie |
| LRU Cache | O(1) access and recency eviction | LRU Cache |
| Segment Tree | Range query plus point update | Segment Tree |
| Fenwick Tree | Prefix sum with compact memory | Fenwick Tree |
Decision Diagram
prefix words -> trie
recent cache -> hashmap + linked list
range query with updates -> segment tree
prefix sums with updates -> Fenwick treeFAQs
Should I learn segment tree before Fenwick tree?
Learn Fenwick first for prefix sums, then segment tree for more flexible range queries.
Is LRU Cache a linked list problem?
It is both linked list and hashmap. The list gives recency order; the map gives O(1) access.