PRACTICE QUESTION STRINGS

Duration: 2 min

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Inside: a video lesson and guided study material.

Module outline

  1. About Course: About the Course
  2. English Language: Vocabulary, Noun, Adjectives, Tenses, Pronoun, Adverb, Preposition, Conjunction, Active Passive Voice (Voice), Articles, Direct and Indirect Speech, Sentence Correction (Error Correction), Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Sentence Completion (Fill in the blanks), Cloze Test (Cloze Passage)
  3. Reasoning: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Puzzle Solving (Puzzles), Seating Arrangements, Blood Relations, Syllogisms, Inequality, Directions (Direction Test), Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Clock, Calendar, Analytical Reasoning (Counting Figures Reasoning), Selection Decision Table (Decision Making), Cubes & Dices, Machine Input-Output
  4. Quantitative Aptitude: Ratio and Proportion (Ratios), Data Interpretation, Mixture and Alligation, Permutation and Combination, Number System, Sequence and Series (Series), Speed Time and Distance, Algebra, Speed Mathematics and Basic Mathematics, Percentage, Average, Time and Work, Simple Interest and Compound Interest, Profit and Loss, Age Problems, Partnership, Mensuration and Geometry, Probability, IBPS Specific Videos
  5. Data Structures - Professional Knowledge: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing
  6. Algorithms- Professional Knowledge: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos
  7. Python- Professional Knowledge: Python for Placements by Yash Sir, Python Basics
  8. Operating System- Professional Knowledge: Introduction to OS, Process Management, CPU Scheduling, Deadlock, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling, File Management
  9. DBMS + SQL- Professional Knowledge: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), File Organization & Indexing, SQL, Transaction Management, Concurrency Control
  10. Computer Networks- Professional Knowledge: Introduction to CN, Data Communication, Net Layer: IP Addressing, Net Layer: IPv4 & Proto, Application Layer, Hardware basics, Network Security
  11. Software Engineering- Professional Knowledge: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
  12. Computer Organization & Microprocessor- Professional Knowledge: Basics of COA, Cache Memory Organization, Programming the Basic Computer
  13. Digital Logic Design- Professional Knowledge: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation
  14. Theory of Computation- Professional Knowledge: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Regular Language Properties, Pushdown Automata & CFG, Turing Machines
  15. Compiler Design- Professional Knowledge: Intro to Compilers, Lexical Analysis, Grammar & CFG, Syntax Analysis: Top-Down, Intermediate Code Gen, Code Optimization
  16. Programming Languages- Professional Knowledge: C Programming by Yash Sir, Object Oriented Programming (OOPS), Programming in C++, Java, C Language Core
  17. Emerging Tech- Professional Knowledge: Emerging Tech Trends
  18. Artificial Intelligence: Artificial Intelligence
  19. Unit Test - Professional Knowledge:
  20. Full Length Mock Test:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The video features a lecture solving a multiple-choice question regarding the number of substrings of all lengths for a character string of length n. The question displays four options: a) n!, b) n^2, c) n(n-1)/2 - 1, and d) n(n+1)/2 + 1. The instructor highlights the phrase "substrings (of all lengths inclusive)" to clarify the problem scope. He uses the string "GATE" as a concrete example, noting its length is n=4. He systematically lists the substrings: single characters (G, A, T, E), pairs (GA, AT, TE), triplets (GAT, ATE), and the full string (GATE). He counts these to arrive at a total of 11. He then substitutes n=4 into the formulas for options (c) and (d). Option (c) results in 5, while option (d) results in 11. Since his manual count matches option (d), he selects it as the correct answer.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor begins by reading the question: "The number of substrings (of all lengths inclusive) that can be formed from a character string of length n is". He uses a red pen to circle the key terms "substrings" and "of all lengths inclusive" on the screen. To solve this, he writes the example string "GATE" on the digital whiteboard. He breaks down the substrings of "GATE" into groups based on their length: length 1 includes G, A, T, E; length 2 includes GA, AT, TE; length 3 includes GAT, ATE; and length 4 is GATE. He writes "n=4" to denote the length of the example string. He then proceeds to evaluate the given options by substituting n=4. He calculates the value for option (c) n(n-1)/2 - 1, writing "4(3)/2 - 1" which equals 5. He circles the result "5". Next, he evaluates option (d) n(n+1)/2 + 1, writing "4(5)/2 + 1" which equals 11. He writes "11" next to his list of substrings, indicating that he has counted 11 substrings in total.

  2. 2:00 – 2:09 02:00-02:09

    The instructor concludes the problem by finalizing his selection. He has circled the number "11" which corresponds to his manual count of substrings for the string "GATE". He then circles option (d) n(n+1)/2 + 1, confirming it as the correct formula based on the example. The final frame shows the circled option (d) and the calculated value 11, solidifying the connection between the example count and the algebraic expression.

The instructor demonstrates a problem-solving strategy for combinatorial string problems by using a concrete example to verify general formulas. By breaking down the string "GATE" into its constituent substrings and counting them to get 11, he establishes a baseline. He then validates this count against the provided algebraic options, finding that option (d) yields the same value (11) when n=4. This confirms option (d) as the correct answer in the context of this specific problem instance.

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