Data Structures — GATE CS Complete Study Guide
The highest-weighted topic in GATE CS (combined with Algorithms: 10–14 marks). Arrays to advanced trees — master every structure with time complexity, GATE examples, and worked problems.
Last updated: April 2026 | GATE CS 2024–2026 syllabus
What You Will Learn
- Arrays and strings — memory layout, 2D addressing, string operations and pattern matching (KMP, Rabin-Karp).
- Linked lists — singly, doubly, circular; insertion/deletion/reversal; Floyd’s cycle detection.
- Stacks and queues — array and linked-list implementations; applications: expression evaluation, BFS.
- Trees — binary trees, traversals, BST operations, AVL rotations, height/node GATE formulae.
- Heaps and priority queues — max/min-heap, heapify, heap sort, time complexity proofs.
- Hashing — hash functions, collision resolution (chaining, open addressing), load factor analysis.
- Graph representations — adjacency matrix vs list, BFS, DFS, complexity comparison.
- Advanced trees — B-trees, B+ trees, Red-Black trees, Segment trees — used in DBMS and OS questions.
- Formula sheet — all key complexity results in one page for last-minute revision.
Topics in This Cluster
Arrays & Strings
1D/2D array memory addressing, row-major vs column-major, string operations, KMP pattern matching, Rabin-Karp algorithm.
Linked Lists
Singly, doubly, circular linked lists; insertion, deletion, reversal; Floyd’s cycle detection; merge of sorted lists.
Stacks & Queues
Stack/queue implementations; infix-postfix-prefix conversion; expression evaluation; circular queue; deque.
Trees & BST
Binary trees, traversals (in/pre/post/level), BST insert/delete/search, AVL trees and rotations, height/node formulae.
Heaps & Priority Queues
Max/min-heap properties, heapify O(n) proof, heap sort, priority queue operations, d-ary heaps.
Hashing
Hash functions, chaining, open addressing (linear, quadratic, double hashing), load factor, expected search time analysis.
Graph Representation & Traversals
Adjacency matrix vs adjacency list, BFS, DFS, time/space complexity, topological sort, connected components.
Advanced Trees
B-trees and B+ trees (DBMS context), Red-Black trees, Segment trees, Fenwick (BIT) trees — properties and GATE applications.
Data Structures Formula Sheet
All time/space complexities, formulae, and key properties consolidated for rapid GATE revision.
GATE CS Weightage — Data Structures
| Topic | Avg. Marks | Common Question Types |
|---|---|---|
| Trees & BST / AVL | 2–4 marks | Height, rotations, traversal output, node count |
| Hashing | 1–2 marks | Collision, probe sequence, expected search time |
| Stacks & Queues | 1–2 marks | Expression conversion, queue simulation |
| Graphs (DS part) | 1–2 marks | BFS/DFS trace, adjacency structure |
| Heaps | 1 mark | Heapify, heap sort steps |
| Arrays & Linked Lists | 1 mark | Address calculation, pointer manipulation |
| Total | 5–8 marks | — |