Stack recursion Practice questions

Duration: 3 min

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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
  13. Digital Society & Cyber Law: Society, Law & Ethics
  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 presents a computer science problem involving a recursive function named `fun(int x, int y)`. The instructor systematically breaks down the execution of the function by tracing each recursive step on a digital whiteboard. The function logic is defined with a base case `if (x == 0) return y;` and a recursive step `return fun(x - 1, x + y);`. The instructor starts by initializing the parameters `x=4` and `y=3`. He then demonstrates how the function calls itself with modified arguments, decrementing `x` by 1 and adding the current value of `x` to `y` in each step. This process continues until the base case is met. The final result is identified as 13, corresponding to option (A).

Chapters

  1. 0:00 – 2:00 00:00-02:00

    In this initial segment, the instructor introduces the problem statement and the function definition. He writes `fun(4, 3)` on the board and assigns the initial values `x=4` and `y=3`. He checks the condition `if (x == 0)`, which evaluates to false. Consequently, he proceeds to the recursive call `fun(x - 1, x + y)`. He writes down the next call `fun(3, 7)`, showing the calculation `4-1=3` and `4+3=7`. He continues this process, writing `fun(2, 10)` where `x` becomes 2 and `y` becomes `3+7=10`. The instructor then writes `fun(1, 12)`, updating `x` to 1 and `y` to `2+10=12`. The board fills with the sequence of function calls, illustrating the recursive nature of the code.

  2. 2:00 – 3:15 02:00-03:15

    In the final segment, the instructor completes the trace of the recursive function. He writes the next call `fun(0, 13)`, where `x` becomes 0 and `y` becomes `1+12=13`. At this point, the condition `if (x == 0)` evaluates to true. The instructor indicates that the function returns the value of `y`, which is 13. He circles the number 13 on the board to highlight the final result. He then writes `(13) Ans` and places a checkmark next to option (A) 13, confirming it as the correct answer.

The lesson effectively demonstrates the evaluation of a recursive function by manually tracing its execution stack. By breaking down the problem into discrete steps, the instructor clarifies how parameters change with each recursive call. The visual aid of writing out each call on the board helps students follow the logic, from the initial call `fun(4, 3)` down to the base case `fun(0, 13)`. This methodical approach ensures a clear understanding of how the final value is derived through successive additions and decrements.

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