PRACTICE QUESTION STRINGS

Duration: 2 min

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Inside: a video lesson and guided study material.

Module outline

  1. HPSC Interview Preparation: Interview Preparation
  2. Python Language: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis, DSA using Python
  3. Data Structure & Algorithms: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Sorting Algorithms, Minimum Spanning Trees, Time Complexity Analysis, Graph Theory, Shortest Path Algos
  4. Computer Networks: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics, Network Security
  5. Computer System & Organisation: Basics of COA, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Control Unit Design, Programming the Basic Computer
  6. Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, SQL, File Organization & Indexing, Transaction Management, Concurrency Control
  7. Operating Systems: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Deadlock, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling
  8. Digital Logic & Circuits: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation
  9. Theory Of Computation: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Pushdown Automata & CFG, Turing Machines, Moore & Mealy Machines
  10. 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. Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management, Data Warehousing & Mining
  12. Introduction to Emerging Trends: Emerging Tech Trends, समुच्चय, संबंध, फलन और विविक्त गणित / Sets, Relations, Functions and Discrete Mathematics, व्यापार, विपणन एवं उपभोक्ता संरक्षण / Trade, Marketing and Consumer Protection, कंप्यूटर नेटवर्क / Computer Networks
  13. Digital Society & Cyber Law: Society, Law & Ethics, साइबर सुरक्षा / Cyber Safety and Security
  14. HPSC PGT Previous Year Paper:
  15. HPSC Assistant Professor Previous Year Paper:
  16. Live Sessions: HPSC Live Sessions, EMRS TGT/PGT Live Class
  17. Full Mock Test:
  18. HPSC PGT - MOCK Test Series:
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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