Linear Probing

Duration: 6 min

This video lesson is available to enrolled students.

Return to /learn/RSSB-BASIC-COMPUTER-INSTRUCTOR/paper-2-data-structures/hashing/open-addressing-probing/asset-linear-probing after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. About the Course: About the Course
  2. Paper-1 & 2 | Basic Numeracy: Ratio and Proportion (Ratios), Divisibility Rules, Mixture and Alligation, Permutation and Combination, Logarithm, Number System, HCF LCM, Sequence and Series (Series), Speed Time and Distance, Percentage, Average, Mensuration and Geometry, Age Problems, Arithmetic, Statistics, Probability, Profit and Loss, Simple Interest and Compound Interest, Partnership, Speed Mathematics and Basic Mathematics, Algebra, Powers and Exponents (Surds and Indices), Time and Work, Pipe and Cistern, RSSB Specific Videos - Basic Numeracy
  3. Paper-1 & 2 | Data Interpretation: Data Interpretation
  4. Paper-1 & 2 | General Mental Ability: Mental Ability, RSSB Specific Videos - Mental Ability
  5. Paper-1 & 2 | Logical Reasoning and Analytical Ability: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Syllogisms, Seating Arrangements, Blood Relations, Directions (Direction Test), Analytical Reasoning (Counting Figures Reasoning), Puzzle Solving (Puzzles), Calendar, Clock, Cubes & Dices, Venn Diagram, Analogy, Ranking, Order and Sequence, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Data Arrangement, Logical Sequence Of Words, Crypt Arithmetic
  6. Paper-1 & 2 | Decision Making and Problem Solving: Selection Decision Table (Decision Making)
  7. Paper-1 | General Science: Physics, Biology, Chemistry, RSSB Specific Videos
  8. Paper-1 | General Awareness: State Wise GK, GK- Current Affairs
  9. Paper - 2 | Digital Logic Systems: Digital Systems & Boolean Basics, Logic Gates & Hardware, Combinational Circuit, Sequential Circuits
  10. Paper-2 | Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, Relational Calculus, Relational Algebra, SQL, NoSQL
  11. Paper-2 | Data Structures & Algorithms: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Algorithm Analysis, Sorting Algorithms, Intro to Compilers, Hashing
  12. Paper 2 | Data Communication and Network Security: Introduction to CN, Data Communication, Data Link Layer - Ethernet, DLL: Error Control, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Application Layer, Hardware basics, Network Security, Ethical Hacking
  13. Paper-2 | Operating Systems: Introduction to OS, Process Management, Memory Management, File Management, Deadlock
  14. Paper-2 | Computer Organization and Architecture: Basics of COA, Floating Point Rep, Cache Memory Organization, Input Output Organisation, Instr Formats & Modes, Control Unit Design, Register Transfer and Microoperations, Programming the Basic Computer, Number System, Number Representation
  15. Paper 2 | System Analysis and Design: Fundamentals of Systems and Information Systems, Fundamentals of Software Engineering, SDLC and Development Approaches, Software Documentation and Software Requirements Specification (SRS), SDD and Quality Assurance, Security, Risk Management & Maintenance, Software Testing
  16. Paper-2 | C Programming: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  17. Paper 2 | OOPS , C++ , JAVA: Language Design, OOPS with C++, Java, .Net Programming, Java Fundamentals
  18. Paper 2 | Python: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis
  19. Emerging Trends and AI: Emerging Tech Trends, Artificial Intelligence
  20. Paper-2 | Data Processing (Ms-Office): MS Office Applications
  21. Paper-2 | Internet and Web Technologies: HTML Basics, CSS, XML, JavaScript-Basics, Internet Fundamentals, Protocols & Services, Web Publishing & Hosting, Server Side & Security, Emerging Technologies, Terms & Abbreviations, Cyber Threats and Malware Attacks, Role of Internet and Web Services, Security in Mobile and Wireless Computing
  22. Paper 2 | Pedagogy: Child Development, Theories, Concept of Pedagogy, Inclusive Education, Experiential Pedagogy, Assessment & Evaluation, Psychology, Curriculum Framework & Reforms, National Education Policy (NEP) 2020
  23. Live Classes: RSSB Live Sessions
  24. Paper 1 - Full Mock Tests:
  25. Paper 2 - Full Mock Tests:
  26. BCI Previous Year Papers:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This lecture segment provides a comprehensive overview of Linear Probing within hash table implementations. The instructor details the sequential search mechanism, emphasizing that operations like insertion, search, and deletion generally achieve constant expected time complexity, provided the load factor remains strictly below one. A significant portion of the lesson is dedicated to the nuances of the deletion operation, explaining why simple removal is insufficient and how special markers are used to preserve search integrity. Finally, the lecture transitions to the disadvantages of this method, specifically focusing on the phenomenon of primary clustering and its detrimental impact on performance as the table fills up.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor begins by defining linear probing as a method that searches the table sequentially starting from the position given by the hash function. He draws a vertical rectangle to represent the hash table structure and writes i, i+1, i+2, and i+3 alongside it to illustrate the probing sequence. The on-screen text highlights that dictionary operations can be implemented in O(1) as long as the load factor is a constant strictly less than one. He explains that for insertion, the algorithm keeps probing until an empty slot is found, while search continues until a matching key is found or an empty slot is reached. He notes that this constant expected time holds when implemented using a random hash function.

  2. 2:00 – 5:00 02:00-05:00

    The discussion moves to the Delete(k) operation, which the instructor marks as interesting in red text. He explains that if a key is simply deleted, subsequent searches for keys that collided and were placed later in the sequence may fail. To solve this, he demonstrates marking slots of deleted keys specially as deleted rather than empty. He writes O(m) next to the table to indicate worst-case time complexity. The instructor then transitions to a new slide titled Disadvantage, preparing to discuss the limitations of this collision resolution scheme. He emphasizes that insert can insert an item in a deleted slot, but search doesn't stop at a deleted slot.

  3. 5:00 – 5:32 05:00-05:32

    The lecturer outlines the disadvantages, specifically underlining primary clustering on the slide. He draws a hash table with a dense cluster of filled slots to visualize how one collision causes more nearby collisions. He writes 1/10 to represent a load factor and circles the cluster, explaining that performance degrades more quickly at high load factors because basic operations take more time. The slide also notes that achieving good performance requires a higher-quality hash function than other schemes. He explains that this is a tendency for one collision to cause more nearby collisions.

The video effectively bridges the gap between theoretical complexity and practical implementation issues. It establishes that while linear probing is efficient on average, the deletion logic is non-trivial and requires special state management. The lesson concludes by identifying primary clustering as a critical flaw, demonstrating through diagrams how collisions propagate and degrade performance, thereby necessitating strict load factor controls and high-quality hash functions for optimal results.

Loading lesson…