Theory of Computation (TOC) for GATE Last Updated : 23 Jul, 2025 Comments Improve Suggest changes 7 Likes Like Report Theory of Computation (TOC) is a key subject in the GATE CSE exam. Here's a complete tutorial on the Theory of Computation for the GATE CSE exam. Whether you're revising or starting fresh, this tutorial will help you prepare effectively.If you have less time to study topic-wise in detail, you may refer to - Theory of Computation Gate Previous Year Questions.IntroductionIntroduction of Theory of ComputationChomsky Hierarchy in TOCRegular Expressions and Finite AutomataIntroduction to Finite Automata (FA)Design Finite Automata from Regular ExpressionsGenerating Regular Expressions from Finite AutomataUnion Process in DFAConcatenation Process in DFAMinimization of DFAConversion from NFA to DFANFA with Epsilon to DFA ConversionRegular Expression, Regular Grammar and Regular LanguagesHow to Write Regular ExpressionsIdentification of Regular LanguageProperties of Regular LanguageClosure Properties of Regular LanguageArden's Theorem in TOCMealy and Moore MachineContext-Free Grammar (CFG) and Push Down Automata (PDA)Introduction to Grammar in TOCRegular GrammarContext Free GrammarAmbiguity in CFG and CFLSimplification of Context Free GrammarConverting CFG to CNF (Chomsky Normal Form)Converting CFG to GNF (Greibach Normal Form)Pumping Lemma in TOCChecking if Language is CFL or NotClosure Properties of Context Free LanguageContext Sensitive Grammar and Context Sensitive LanguageIntroduction to Push Down AutomataDifference Between DPDA and NPDAConstruction of PDATuring MachineRecursive and Recursive Enumerable LanguageTuring Machine in TOCConstruction of Turing MachineHalting Problem in TOCDecidabilityDecidability and Undecidability in TOCUndecidability and Reducibility in TOCDecidability Table in TOCClosure Property Table in TOCClosure Properties Table in TOCOfficial Syllabus of Theory of Computation for GATE CSEHere's the complete syllabus of Theory of Computation, as per the GATE CSE 2025 official notification:Regular expressions and finite automata Context-free grammars and push-down automata Regular and context-free languages, pumping lemmaTuring machines and undecidabilityGATE CS/IT Subject-Wise WeightageThe subject-wise weightage for GATE CSE exam, based on the previous year patterns, is listed below:TopicsWeightageGeneral Aptitude15Engineering Mathematics13Discrete MathematicsDigital Logic6Computer Organization and Architecture8Programming and Data Structure15Algorithms7Theory of Computation6Compiler Design4Operating System9Databases7Computer Networks10Tips For Candidates While Preparing for TOC in GATE ExamsTo do well in the Theory of Computation section of the GATE exam, it's important to focus on key concepts and practice regularly. While the subject might seem tough at first, breaking it down into smaller, manageable parts can make it easier to understand. Understand the Basics First: Start by building a solid foundation of the fundamental concepts, such as automata theory, formal languages, and Turing machines. Without a clear understanding of these basics, advanced topics can become confusing.Focus on Important Topics: Some topics in Theory of Computation carry more weight in the GATE exam. Prioritize studying topics like finite automata, regular languages, context-free grammars, and Turing machines, as these are frequently tested.Practice Regularly: Solve as many practice problems and previous years’ question papers as possible. This will help you get familiar with the types of questions asked and improve your problem-solving speed.Revise Frequently: Theory of Computation requires frequent revision to retain all the concepts. Set aside dedicated time for revision to ensure you don’t forget important details.Understand the Proofs: Don’t just memorize theorems and proofs—understand them. Knowing why a theorem is true will help you tackle tricky problems more effectively.Take Mock Tests: Regularly take mock tests to simulate exam conditions. This will help you assess your preparation level and identify areas that need improvement.This tutorial provides a comprehensive yet straightforward guide to the core concepts of Theory of Computation as per the GATE CSE syllabus. By breaking down each topic and explaining it in simple terms, you'll be well on your way to mastering the subject and excelling in your exam. Create Quiz Maha Marathon - Complete TOC in One Shot | Mallesham Sir | GATE CSE 2025 Comment K kartik Follow 7 Improve K kartik Follow 7 Improve Article Tags : Theory of Computation GATE 2025 Explore Automata _ IntroductionIntroduction to Theory of Computation5 min readChomsky Hierarchy in Theory of Computation2 min readApplications of various Automata4 min readRegular Expression and Finite AutomataIntroduction of Finite Automata3 min readArden's Theorem in Theory of Computation6 min readSolving Automata Using Arden's Theorem6 min readL-graphs and what they represent in TOC4 min readHypothesis (language regularity) and algorithm (L-graph to NFA) in TOC7 min readRegular Expressions, Regular Grammar and Regular Languages7 min readHow to identify if a language is regular or not8 min readDesigning Finite Automata from Regular Expression (Set 1)4 min readStar Height of Regular Expression and Regular Language3 min readGenerating regular expression from Finite Automata3 min readCode Implementation of Deterministic Finite Automata (Set 1)8 min readProgram for Deterministic Finite Automata7 min readDFA for Strings not ending with "THE"12 min readDFA of a string with at least two 0’s and at least two 1’s3 min readDFA for accepting the language L = { anbm | n+m =even }14 min readDFA machines accepting odd number of 0’s or/and even number of 1’s3 min readDFA of a string in which 2nd symbol from RHS is 'a'10 min readUnion Process in DFA4 min readConcatenation Process in DFA3 min readDFA in LEX code which accepts even number of zeros and even number of ones6 min readConversion from NFA to DFA5 min readMinimization of DFA7 min readReversing Deterministic Finite Automata4 min readComplementation process in DFA2 min readKleene's Theorem in TOC | Part-13 min readMealy and Moore Machines in TOC3 min readDifference Between Mealy Machine and Moore Machine4 min readCFGRelationship between grammar and language in Theory of Computation4 min readSimplifying Context Free Grammars6 min readClosure Properties of Context Free Languages11 min readUnion and Intersection of Regular languages with CFL3 min readConverting Context Free Grammar to Chomsky Normal Form5 min readConverting Context Free Grammar to Greibach Normal Form6 min readPumping Lemma in Theory of Computation4 min readCheck if the language is Context Free or Not4 min readAmbiguity in Context free Grammar and Languages3 min readOperator grammar and precedence parser in TOC6 min readContext-sensitive Grammar (CSG) and Language (CSL)2 min readPDA (Pushdown Automata)Introduction of Pushdown Automata5 min readPushdown Automata Acceptance by Final State4 min readConstruct Pushdown Automata for given languages4 min readConstruct Pushdown Automata for all length palindrome6 min readDetailed Study of PushDown Automata3 min readNPDA for accepting the language L = {anbm cn | m,n>=1}2 min readNPDA for accepting the language L = {an bn cm | m,n>=1}2 min readNPDA for accepting the language L = {anbn | n>=1}2 min readNPDA for accepting the language L = {amb2m| m>=1}2 min readNPDA for accepting the language L = {am bn cp dq | m+n=p+q ; m,n,p,q>=1}2 min readConstruct Pushdown automata for L = {0n1m2m3n | m,n ≥ 0}3 min readConstruct Pushdown automata for L = {0n1m2n+m | m, n ≥ 0}2 min readNPDA for accepting the language L = {ambncm+n | m,n ≥ 1}2 min readNPDA for accepting the language L = {amb(m+n)cn| m,n ≥ 1}3 min readNPDA for accepting the language L = {a2mb3m|m>=1}2 min readNPDA for accepting the language L = {amb2m+1 | m ≥ 1}2 min readNPDA for accepting the language L = {aibjckdl | i==k or j==l,i>=1,j>=1}3 min readConstruct Pushdown automata for L = {a2mc4ndnbm | m,n ≥ 0}3 min readNPDA for L = {0i1j2k | i==j or j==k ; i , j , k >= 1}2 min readNPDA for accepting the language L = {anb2n| n>=1} U {anbn| n>=1}2 min readNPDA for the language L ={wЄ{a,b}* | w contains equal no. of a's and b's}3 min readTuring MachineTuring Machine in TOC7 min readTuring Machine for addition3 min readTuring machine for subtraction | Set 12 min readTuring machine for multiplication2 min readTuring machine for copying data2 min readConstruct a Turing Machine for language L = {0n1n2n | n≥1}3 min readConstruct a Turing Machine for language L = {wwr | w ∈ {0, 1}}5 min readConstruct a Turing Machine for language L = {ww | w ∈ {0,1}}7 min readConstruct Turing machine for L = {an bm a(n+m) | n,m≥1}3 min readConstruct a Turing machine for L = {aibjck | i*j = k; i, j, k ≥ 1}2 min readTuring machine for 1's and 2’s complement3 min readRecursive and Recursive Enumerable Languages in TOC6 min readTuring Machine for subtraction | Set 22 min readHalting Problem in Theory of Computation4 min readTuring Machine as Comparator3 min readDecidabilityDecidable and Undecidable Problems in Theory of Computation6 min readUndecidability and Reducibility in TOC5 min readComputable and non-computable problems in TOC6 min readTOC Interview preparationLast Minute Notes - Theory of Computation13 min readTOC Quiz and PYQ's in TOCTheory of Computation - GATE CSE Previous Year Questions2 min read Like