Practice Question Strings

Duration: 3 min

This video lesson is available to enrolled students.

Return to /learn/ISRO/toc-compiler/introduction-to-toc/basics-string-ops/asset-practice-question-strings-1995 after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. About Course: About the Course
  2. General Aptitude & Reasoning: Number System, Percentage, Ratio and Proportion (Ratios), Average, Profit and Loss, Simple Interest and Compound Interest, Time and Work, Speed Time and Distance, Mixture and Alligation, Data Interpretation, Algebra, Probability, Permutation and Combination, Venn Diagram, HCF LCM, Divisibility Rules, Age Problems, Pipe and Cistern, Partnership, Linear Algebra, Sequence and Series (Series), Statistics, Powers and Exponents (Surds and Indices), Arithmetic, Mensuration and Geometry, Calculus, Trigonometry, Vectors, Speed Mathematics and Basic Mathematics, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Analogy, Series (Number and Letter Series) (Numerical Relations and Reasoning), Puzzle Solving (Puzzles), Syllogisms, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Calendar, Seating Arrangements, Coding Decoding, Blood Relations, Directions (Direction Test), Clock, Analytical Reasoning (Counting Figures Reasoning), Ranking, Order and Sequence, Logical Sequence Of Words, Inequality, Data Sufficiency, Cubes & Dices
  3. Computer Networks & Cybersecurity: 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 Security
  4. Programming, Data Structures & Algorithms: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, OOPS with C++, Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Advanced Algorithms
  5. AI, Machine Learning, Big Data & Cloud: Emerging Tech Trends, Artificial Intelligence, Big Data Systems, Approaches to AI, Search Algorithms, Knowledge Representation, Cloud Computing
  6. Digital Logic & Computer Organization: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation, Basics of COA, Floating Point Rep, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Register Transfer and Microoperations, Control Unit Design, Programming the Basic Computer
  7. TOC & Compiler: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Moore & Mealy Machines, Pushdown Automata & CFG, Turing Machines, Complexity Theory, 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
  8. Discrete Mathematics: Set Theory, Relations, Functions, Graph Theory, Group Theory, Propositional and Predicate Logic
  9. Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management, Unix OS, Linux OS, Distributed Systems
  10. Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management, Object Oriented Technology, HTML Basics, JavaScript-Basics, Java, XML
  11. Database Management System: 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, Database Recovery, Data Warehousing & Mining, Enhanced Data Models, NoSQL
  12. Other Recurring CS Topics: Basics of Computer Graphics, 2-D Geometrical Transforms and Viewing, Multimedia
  13. Live Classes: ISRO Live classes
  14. Full Mock Test:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The video presents a discrete mathematics problem concerning binary strings without consecutive zeros. The instructor defines $x_n$ as the count of such strings of length $n$ and asks to identify the correct recurrence relation from four options. He systematically calculates the first few terms ($x_0$ through $x_3$) by listing valid strings to verify the base cases. By testing these values against the given options, he eliminates incorrect formulas and identifies the Fibonacci-like recurrence $x_n = x_{n-1} + x_{n-2}$. Finally, he uses this recurrence to compute $x_5$, selecting the correct numerical answer from the provided choices.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor introduces the problem statement: finding the recurrence for binary strings of length $n$ with no consecutive 0s. He writes down the four options on the screen: $x_n = 2x_{n-1}$, $x_n = x_{\lfloor n/2 floor} + 1$, $x_n = x_{\lfloor n/2 floor} + n$, and $x_n = x_{n-1} + x_{n-2}$. He begins by determining base cases, writing $x_0 = 1$ for the empty string and $x_1 = 2$ for strings "0" and "1". He then lists valid strings for length 2 ("01", "10", "11") to find $x_2 = 3$. For length 3, he lists "010", "011", "101", "110", "111" to find $x_3 = 5$. He tests option (a) $x_n = 2x_{n-1}$ and finds it fails for $x_2$ since $3 eq 4$. He tests option (b) and (c) and finds they fail. He tests option (d) $x_n = x_{n-1} + x_{n-2}$, verifying $x_2 = x_1 + x_0$ ($3 = 2+1$) and $x_3 = x_2 + x_1$ ($5 = 3+2$), confirming it is the correct recurrence.

  2. 2:00 – 3:06 02:00-03:06

    The instructor proceeds to the second question asking for the value of $x_5$. He continues the sequence established by the recurrence relation $x_n = x_{n-1} + x_{n-2}$. He calculates $x_4$ by adding $x_3$ and $x_2$ ($5 + 3 = 8$). Then he calculates $x_5$ by adding $x_4$ and $x_3$ ($8 + 5 = 13$). He circles the value 13 on the board. He identifies 13 as the correct answer, corresponding to option (c), and marks it.

The lesson demonstrates a standard method for solving recurrence relation problems: calculating initial terms to identify the pattern. By explicitly listing small cases, the instructor validates the Fibonacci sequence structure inherent in the problem constraints. The progression from identifying the recurrence to applying it for a specific term ($x_5$) reinforces the practical application of the derived formula.

Loading lesson…