Practice Question - 3

Duration: 4 min

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Inside: a video lesson and guided study material.

Module outline

  1. About Course: About the Course
  2. Paper-2 | Programming & Data Structures: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing
  3. Paper-2 | Databases / DBMS & SQL: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, SQL, Relational Calculus, Transaction Management, Concurrency Control
  4. Paper-2 | Algorithms: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos
  5. Paper-2 | Computer Networks & Security: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, DLL: Error Control, DLL: Framing, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Net Layer:Routing Protocol, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware Basics, Network Access Technologies, Network Security
  6. Paper-2 | Digital Logic: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation, Floating Point Rep
  7. Paper-2 | Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management
  8. Paper-2 | Theory of Computation: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Moore & Mealy Machines, Pushdown Automata & CFG, Turing Machines
  9. Paper-2 | Computer Organization & Architecture: Basics of COA, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Control Unit Design, Programming the Basic Computer
  10. Paper-2 | Compiler Design: Intro to Compilers, Lexical Analysis, Grammar & CFG, Syntax Analysis: Top-Down, Syntax Analysis: Bottom-Up, Semantic Analysis & SDT, Intermediate Code Gen, Code Optimization, Run Time Environment
  11. Paper-1 | General Awareness: Polity, Physics, Biology, Chemistry, Static General Knowledge, GK- Current Affairs, History, Geography, Indian Economy, Environment
  12. Paper-1 | Logical Reasoning: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Data Interpretation, Blood Relations, Syllogisms, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Selection Decision Table (Decision Making), Clock, Calendar, Cubes & Dices, Directions (Direction Test), Analogy, Seating Arrangements, Analytical Reasoning (Counting Figures Reasoning)
  13. Paper-1 | Quantitative Aptitude: Ratio and Proportion (Ratios), Mixture and Alligation, Permutation and Combination, Number System, HCF LCM, Speed Time and Distance, Average, Age Problems, Percentage, Profit and Loss, Time and Work, Pipe and Cistern, Simple Interest and Compound Interest, Powers and Exponents (Surds and Indices), Mensuration and Geometry, Probability, Statistics, Arithmetic, Algebra
  14. Paper-1 | English: Vocabulary, Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Sentence Correction (Error Correction), Sentence Completion (Fill in the blanks), Sentence Construction, Cloze Test (Cloze Passage)
  15. Coal India Previous Year Paper:
  16. Engineering Mathematics: Set Theory, Relations, Functions, Graph Theory, Group Theory, Propositional and Predicate Logic, Linear Algebra, Calculus
  17. Coal India Mock Test:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The video lecture presents a step-by-step construction of a Pushdown Automaton (PDA) for the language $L = \{ww^r \mid w \in \{a, b\}^*\}$. The instructor defines the language as a string $w$ concatenated with its reverse $w^r$. He illustrates this with the example $w = aaba$, resulting in $aabaabaa$. The lecture focuses on drawing the PDA state diagram, starting with an initial state $q_0$ that pushes input symbols onto the stack. He introduces a non-deterministic transition to state $q_1$ to guess the midpoint and match the reverse string by popping symbols. The session concludes with a theoretical overview of Non-Deterministic PDAs (NPDA), defining them using 7 tuples and explaining the transition function that allows movement to multiple states.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor introduces the problem statement: "Construct pda that accepts a language $L = \{ww^r \mid w \in \{a, b\}^*\}$". He explains the language structure where a string $w$ is followed by its reverse $w^r$. He provides an example: $w = aaba$ and $w^r = abaa$, forming $aabaabaa$. He begins the PDA construction by drawing the initial state $q_0$ with a self-loop. He writes transition rules like $a, a / aa$, $a, b / ab$, $b, a / ba$, and $b, b / bb$. These transitions show the PDA pushing input symbols onto the stack to store $w$. He also draws a transition from $q_0$ to state $q_1$ labeled $a, a / \epsilon$ and $b, b / \epsilon$, representing the non-deterministic choice to start matching the reverse string.

  2. 2:00 – 4:08 02:00-04:08

    The instructor refines the PDA diagram, circling the transition from $q_0$ to $q_1$ to highlight the non-deterministic guess of the string's midpoint. He explains that in state $q_1$, the PDA matches input against the stack. He draws a self-loop on $q_1$ with transitions $a, a / \epsilon$ and $b, b / \epsilon$, popping the stack if inputs match. A transition to final state $q_2$ with $\epsilon, Z / Z$ indicates acceptance. The video then shifts to a slide titled "Non-Deterministic PDA". It defines an NPDA using 7 tuples and highlights the transition function $\delta: Q imes (\Sigma \cup \{\epsilon\}) imes \Gamma o 2^{Q imes \Gamma^*}$. The instructor explains that an NPDA can move to multiple states for a given input and stack symbol, essential for languages like palindromes where the midpoint is unknown. He notes that the rest of the tuples remain the same as a DPDA.

The lecture bridges practical construction and theoretical definition. It demonstrates how non-determinism allows PDAs to handle unknown midpoints in palindromes by pushing the first half and non-deterministically switching to pop and match the second half. The session concludes by formalizing this concept through the mathematical definition of an NPDA.

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