Linked listPractice Question

Duration: 3 min

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Inside: a video lesson and guided study material.

Module outline

  1. About Course: About the Course
  2. Paper-2 | Programming & Data Structures: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing
  3. Paper-2 | Databases / DBMS & SQL: 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
  4. Paper-2 | Algorithms: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos
  5. Paper-2 | Computer Networks & Security: 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 Access Technologies, Network Security
  6. Paper-2 | Digital Logic: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation, Floating Point Rep
  7. Paper-2 | Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management
  8. Paper-2 | Theory of Computation: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Moore & Mealy Machines, Pushdown Automata & CFG, Turing Machines
  9. Paper-2 | Computer Organization & Architecture: Basics of COA, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Control Unit Design, Programming the Basic Computer
  10. Paper-2 | 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. Paper-1 | General Awareness: Polity, Physics, Biology, Chemistry, Static General Knowledge, GK- Current Affairs, History, Geography, Indian Economy, Environment
  12. Paper-1 | Logical Reasoning: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Data Interpretation, Blood Relations, Syllogisms, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Selection Decision Table (Decision Making), Clock, Calendar, Cubes & Dices, Directions (Direction Test), Analogy, Seating Arrangements, Analytical Reasoning (Counting Figures Reasoning)
  13. Paper-1 | Quantitative Aptitude: Ratio and Proportion (Ratios), Mixture and Alligation, Permutation and Combination, Number System, HCF LCM, Speed Time and Distance, Average, Age Problems, Percentage, Profit and Loss, Time and Work, Pipe and Cistern, Simple Interest and Compound Interest, Powers and Exponents (Surds and Indices), Mensuration and Geometry, Probability, Statistics, Arithmetic, Algebra
  14. Paper-1 | English: Vocabulary, Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Sentence Correction (Error Correction), Sentence Completion (Fill in the blanks), Sentence Construction, Cloze Test (Cloze Passage)
  15. Coal India Previous Year Paper:
  16. Engineering Mathematics: Set Theory, Relations, Functions, Graph Theory, Group Theory, Propositional and Predicate Logic, Linear Algebra, Calculus
  17. Coal India Mock Test:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This educational video features Sanchit Jain from KnowledgeGate explaining how to reverse a singly linked list in C. The lecture begins by presenting a function `reverse` that accepts a double pointer `head_ref`. The instructor details the iterative algorithm, initializing `prev` to NULL and `current` to the head. He draws a diagram of nodes A, B, C, and D to illustrate the pointer manipulation. The core logic involves a `while` loop that iterates through the list, reversing the `next` pointer of each node to point to the previous node. The lesson culminates in identifying the missing statement required to update the head of the list after the reversal is complete.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor introduces the problem of reversing a singly linked list. He displays the C code for the `reverse` function, highlighting the initialization of `prev` to NULL and `current` to `*head_ref`. He draws a diagram of a linked list (A->B->C->D) and explains the `while` loop logic: saving the next node, reversing the current node's pointer to point to `prev`, and moving `prev` and `current` forward. He emphasizes that `head_ref` is a double pointer. He draws arrows to show the reversal process, explaining how `current` moves from the head to the tail while `prev` moves from NULL to the new head.

  2. 2:00 – 2:58 02:00-02:58

    The instructor focuses on the missing line at the end of the function. He presents multiple-choice options for the final statement: (A) `*head_ref = prev;`, (B) `*head_ref = current;`, (C) `*head_ref = next;`, and (D) `*head_ref = NULL;`. He explains that after the loop finishes, `prev` points to the new head of the reversed list. Since `head_ref` is a double pointer, it needs to be updated to point to this new head. He concludes that `*head_ref = prev;` is the correct statement to update the head pointer, selecting option (A) and circling it on the screen.

The lecture progresses from explaining the iterative reversal algorithm to identifying the critical final step. The instructor uses visual aids (diagrams) and code analysis to demonstrate how pointers are manipulated. The key takeaway is understanding that reversing the internal pointers of nodes is not enough; the external head pointer must also be updated to point to the new first node, which is the last node processed in the loop (stored in `prev`). This ensures the list is correctly accessible from the new head.

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