SUBJECT NOTEBOOK|Computer Science & Data Science · GATE CS/IT & DA

Algorithms

“Master asymptotic analysis, Master Theorem, divide-and-conquer recurrences, greedy matroid optimality, dynamic programming memoization, graph traversals, shortest paths, and NP-completeness reductions.”

A rigorous, mathematically formal study notebook covering asymptotic growth hierarchies, recurrence trees, comparison sorting lower bounds, linear-time selection, Huffman coding, minimum spanning trees, 0/1 Knapsack, matrix chain multiplication, graph traversals, Dijkstra, Bellman-Ford, Floyd-Warshall, and Cook-Levin reduction chains for semester examinations and top-percentile GATE CS/IT & DA performance.

05 SECTIONS · 11 NOTES · 00 LABS
MODE 01 · UNDERSTAND & LEARN

Structured Notes & Exam Lens

Two parallel study perspectives

A · B.Tech Structured Study Sequence

5 Sections · Full Curriculum
01

Asymptotic Notations & Recurrences

2 notes

Formal mathematical definitions of Big-O, Omega, Theta, Little-o, Little-omega, limit quotients, dominance hierarchies, recurrence trees, and standard/extended Master Theorem cases.

1.1Asymptotic Bounds, Order of Growth & Growth Hierarchy

Formal definitions of O, Omega, Theta, o, omega, limit tests, Stirling's approximation, and dominance ranking.

1.2Master Theorem, Recurrences & Advanced Recurrence Solvers

Comparing f(n) with n^{log_b a}, extended Master cases, substitution proofs, and change of variables.

02

Sorting, Selection & Priority Queues

2 notes

Merge Sort inversion counting, Lomuto vs Hoare partitions, randomized quicksort expected bounds, deterministic median-of-medians linear selection, decision tree lower bounds, non-comparison sorting, and binary heap mathematics.

2.1Merge Sort, Quick Sort & Linear-Time Selection

Inversion counting, Hoare vs Lomuto partitions, randomized quicksort expected O(n log n), and BFPRT Median-of-Medians.

2.2Sorting Bounds, Non-Comparison Sorting & Binary Heaps

Omega(n log n) decision tree bound, Counting/Radix/Bucket sort, linear-time Build-Heap, and Heap Sort.

03

Greedy Strategies & Dynamic Programming

4 notes

Greedy choice property, exchange arguments, Huffman coding, minimum spanning trees (Kruskal with DSU, Prim), 0/1 Knapsack pseudo-polynomial bounds, LCS, LIS, and Matrix Chain Multiplication parenthesizations.

3.1Greedy Choice, Huffman Coding & Interval Scheduling

Optimal substructure vs greedy-choice property, activity selection, and Huffman prefix codes.

3.2Minimum Spanning Trees: Kruskal, Prim & Cut Properties

Cut Property, Cycle Property, Kruskal with DSU, Prim with priority queues, and uniqueness theorems.

3.3Dynamic Programming: 0/1 Knapsack, LCS & LIS

Overlapping subproblems, 0/1 Knapsack pseudo-polynomial complexity, LCS table reconstruction, and LIS in O(n log n).

3.4Matrix Chain Multiplication & Optimization Problems

Optimal parenthesization, Catalan number state space, O(n^3) table formulation, and DP on DAGs.

04

Graph Traversals & Shortest Paths

2 notes

Adjacency representations, BFS level frontiers, DFS discovery/finish timestamps, edge classification (tree, back, forward, cross), Topological Sort, Kosaraju/Tarjan SCCs, Dijkstra with heaps, Bellman-Ford negative cycle detection, Floyd-Warshall, and Johnson's algorithm.

4.1Graph Traversals, Topological Sort & Strongly Connected Components

BFS/DFS edge classification, discovery/finish timestamps, Kahn's algorithm, and Kosaraju/Tarjan SCCs.

4.2Shortest Paths: Dijkstra, Bellman-Ford, Floyd-Warshall & Johnson

Non-negative edge Dijkstra, negative edge relaxation, negative cycle detection, and all-pairs dynamic programming.

05

Computational Complexity & NP-Completeness

1 note

Decision problems, complexity classes P, NP, co-NP, NP-Hard, NP-Complete, polynomial certificates, Cook-Levin theorem, and classic polynomial-time reduction chains.

5.1Complexity Classes P, NP, NP-Complete & Reductions

Deterministic vs non-deterministic polynomial time, polynomial certificates, Cook-Levin theorem, and reduction chains.

B · GATE 2027 Syllabus Scope

Official syllabus scope and related lesson coverage; topics outside the syllabus are marked as enrichment.

GATE 2027 CS/IT + DA scope
Official syllabus topics:
  • •Asymptotic analysis: Big-O, Omega, Theta, Little-o, Little-omega notations, order of growth hierarchy
  • •Recurrence relations: Substitution method, recursion trees, Master Theorem (standard and extended cases)
  • •Divide-and-Conquer: Merge Sort, Quick Sort (partition schemes, randomized expected time), linear-time selection (QuickSelect, Median-of-Medians)
  • •Sorting bounds and priority queues: Comparison sorting lower bound Omega(n log n), Counting Sort, Radix Sort, Bucket Sort, binary heaps, linear-time Build-Heap, Heap Sort
  • •Greedy algorithms: Greedy choice property, optimal substructure, Fractional Knapsack, Activity/Interval Selection, Huffman prefix codes
  • •Minimum Spanning Trees: Cut Property, Cycle Property, Kruskal with Disjoint Set Union (DSU), Prim's algorithm, uniqueness conditions
  • •Dynamic programming: Overlapping subproblems, 0/1 Knapsack (pseudo-polynomial time), Longest Common Subsequence (LCS), Longest Increasing Subsequence (LIS)
  • •Advanced dynamic programming: Matrix Chain Multiplication (Catalan number bounds), DP on DAGs, Held-Karp TSP
  • •Graph traversals and connectivity: Adjacency representations, BFS, DFS edge classification (tree, back, forward, cross), Topological Sort (Kahn's and DFS), Strongly Connected Components (Kosaraju, Tarjan)
  • •Shortest paths: BFS for unweighted graphs, DAG topological relaxation, Dijkstra with heaps, Bellman-Ford negative cycle detection, Floyd-Warshall APSP, Johnson's algorithm
  • •Computational complexity: Classes P, NP, co-NP, NP-Hard, NP-Complete, polynomial-time reductions, Cook-Levin theorem, classic NP-complete reductions
MODE 02 · ACTIVE PRACTICE

Interactive Labs & Verified PYQs

0 Simulators · 0 Verified Questions
MODE 03 · HIGH-SPEED RETRIEVAL

Revision & Rapid Review Sheets

One-page mental models
MODE 04 · ACADEMIC CITATION TRAIL

Authoritative Textbooks & Video Lectures

Primary Sources
Recommended Textbooks

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MODE 05 · OPEN STUDENT COLLABORATION

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