Last Updated: November 21, 2025
Data Structures
Essential data structures reference
Arrays & Lists
| Item | Description |
|---|---|
Array
|
Fixed size, O(1) access |
Dynamic Array
|
Resizable, amortized O(1) append |
Linked List
|
O(1) insertion/deletion at head |
Doubly Linked List
|
Bidirectional traversal |
Circular List
|
Last node points to first |
Stacks & Queues
| Item | Description |
|---|---|
Stack
|
LIFO - Last In First Out |
Queue
|
FIFO - First In First Out |
Priority Queue
|
Elements with priorities |
Deque
|
Double-ended queue |
Circular Queue
|
Fixed-size with wrap-around |
Trees
| Item | Description |
|---|---|
Binary Tree
|
Each node has ≤2 children |
Binary Search Tree
|
Left < Parent < Right |
AVL Tree
|
Self-balancing BST |
Red-Black Tree
|
Balanced BST with color |
Heap
|
Complete tree, parent > children |
Trie
|
Prefix tree for strings |
B-Tree
|
Self-balancing, multiple keys |
Hash & Graphs
| Item | Description |
|---|---|
Hash Table
|
O(1) average lookup |
Hash Set
|
Unique elements only |
Graph
|
Vertices and edges |
Directed Graph
|
One-way edges |
Weighted Graph
|
Edges have weights |
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