Stack Practice questions
Duration: 10 min
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Inside: a video lesson and guided study material.
Module outline
- Quantitative Ability: Percentage, Profit and Loss, Ratio and Proportion (Ratios), Average, Time and Work, Speed Time and Distance, Simple Interest and Compound Interest, Age Problems, Number System, Divisibility Rules, HCF LCM, Algebra, Permutation and Combination, Probability, Data Interpretation, Logarithm, Sequence and Series (Series), Powers and Exponents (Surds and Indices), Speed Mathematics and Basic Mathematics
- Logical Reasoning: Seating Arrangements, Puzzle Solving (Puzzles), Data Arrangement, Coding Decoding, Blood Relations, Directions (Direction Test), Ranking, Order and Sequence, Data Sufficiency, Venn Diagram, Inequality, Series (Number and Letter Series) (Numerical Relations and Reasoning), Logical Sequence Of Words, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Selection Decision Table (Decision Making), Analogy, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning)
- Verbal Ability: Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Subject Verb Agreement (Verb Noun Agreement), Tenses, Articles, Preposition, Conjunction, Modals, Active Passive Voice (Voice), Direct and Indirect Speech, Vocabulary, Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Sentence Completion (Fill in the blanks), Sentence Correction (Error Correction), Cloze Test (Cloze Passage), Facts, Inference and Judgements
- Programming Fundamentals (Technical): C Fundamentals
- Data Structures (Technical): Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing
- Algorithms (Technical): Algorithm Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Time Complexity Analysis, Advanced Algorithms
- OOPs (Technical): Object Oriented Programming (OOPS)
- DBMS (Technical): Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, Relational Calculus, Transaction Management, Concurrency Control, Database Recovery, ORDBMS, Database Security & Authorization, Query Processing & Optimization, Enhanced Data Models, Data Warehousing & Mining, Big Data Systems, NoSQL
- SQL (Technical): SQL
- Operating Systems (Technical): Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Deadlock, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling, File Management, Windows OS, Linux OS, Security, Distributed Systems, Virtual Machines
- Computer Networks (Technical): 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, Mobile Technology, Cloud Computing and IoT, Cyber and Info Security
- Software Engineering (Technical): Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
- Coding/Automata Round: Coding Questions by Yash Sir, C Programming by Yash Sir, Programming in C++, Java, Python for Placements by Yash Sir, Pseudo Codes
- Personality / Behavioral Assessment: Behavioral Assessment (Behavioral Competency Profiling) (Psychometric Test)
- Writing Assessment: English Writing Ability
AI summary & chapters
AI Summary
An AI-generated summary of this video lecture.
The video lecture analyzes two C functions, `fun` and `fun2`, to determine the mathematical operation performed by `fun2`. The instructor first identifies that `fun(x, y)` implements multiplication (`x * y`). He then traces the execution of `fun2(a, b)` using specific inputs (a=2, b=3) to find the output. By expanding the recursive calls, he calculates the result as 8. Finally, he generalizes the recursive structure of `fun2` to show that it computes `a` raised to the power of `b` (exponentiation), confirming option (C) as the correct answer.
Chapters
0:00 – 2:00 00:00-02:00
The instructor introduces the problem by displaying two C functions on the screen: `fun(int x, int y)` and `fun2(int a, int b)`. He begins by analyzing `fun`, noting that it recursively adds `x` to itself `y` times, effectively implementing multiplication (`x * y`). He then sets up a trace for `fun2` using the specific input values `a=2` and `b=3`. He writes down the initial recursive expansion on the whiteboard: `fun2(2, 3)` calls `fun(2, fun2(2, 2))`. He continues to expand the inner call, writing `fun(2, fun(2, fun2(2, 1)))` and then `fun(2, fun(2, fun(2, fun2(2, 0))))`. This establishes the recursive structure needed to evaluate the function.
2:00 – 5:00 02:00-05:00
The instructor proceeds to evaluate the nested function calls starting from the base case. He identifies that `fun2(2, 0)` returns `1` based on the base condition `if (b == 0) return 1;`. Substituting this back, the expression becomes `fun(2, fun(2, fun(2, 1)))`. He evaluates the innermost `fun(2, 1)` as `2 * 1 = 2`. The expression simplifies to `fun(2, fun(2, 2))`. Next, he evaluates `fun(2, 2)` as `2 * 2 = 4`. The expression further simplifies to `fun(2, 4)`. Finally, he calculates `fun(2, 4)` as `2 * 4 = 8`. He writes `2^3 = 8` on the board, noting that the result matches the power operation.
5:00 – 9:52 05:00-09:52
To confirm the general behavior, the instructor analyzes the recursive step of `fun2` algebraically. He observes that `fun2(a, b)` returns `fun(a, fun2(a, b-1))`. Since `fun(x, y)` is multiplication, this translates to `a * fun2(a, b-1)`. This recurrence relation, `f(a, b) = a * f(a, b-1)` with base case `f(a, 0) = 1`, is the standard definition of exponentiation `a^b`. He compares this with the given options: (A) `a*b`, (B) `a+a*b`, (C) `a^b`, and (D) `b^a`. Although option (B) also yields 8 for inputs (2,3), the recursive structure `a * fun2(...)` clearly matches exponentiation, not addition. He circles option (C) `a^b` as the correct answer, concluding that `fun2` computes `a` raised to the power of `b`.
The lecture demonstrates a method for analyzing recursive C functions by first simplifying helper functions and then tracing specific examples to find a pattern. By identifying `fun` as multiplication and tracing `fun2(2, 3)` to get 8, the instructor establishes a numerical pattern. He then generalizes the recursive step `fun(a, fun2(a, b-1))` into the algebraic form `a * fun2(a, b-1)`, which definitively proves that `fun2` implements exponentiation `a^b`.