Threaded Binary Tree

Duration: 15 min

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  1. About Course: UPPSC Course Overview
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  3. Paper 1 | General Hindi: भाषा, लिपि, ध्वनि, वर्ण, अक्षर, स्वर, व्यंजन, मात्रा और संयुक्ताक्षर, वर्तनी, वर्ण-विन्यास, अनुस्वार, अनुनासिक, चंद्रबिंदु और ‘र’ के रूप, शब्द, पद और शब्द-भेद, संज्ञा और सर्वनाम, विशेषण और क्रिया, लिंग, वचन, पुरुष और कारक, काल, वाच्य, वाक्य और वाक्य-भेद, वर्णमाला, समास, संधि, विलोम शब्द, पर्यायवाची शब्द, सामान्य अशुद्धियाँ, अनेक शब्दों के लिए एक शब्द, मुहावरे और लोकोक्तियाँ, अपठित गद्यांश और अपठित पद्यांश, Multi-Topic Content (Cross-Concept Material), शब्द-भंडार, वर्ण-विचार, हिन्दी की ध्वनि और स्वनिम व्यवस्था, प्राचीन और मध्यकालीन भारतीय आर्यभाषाएँ, काव्य के लक्षण, हेतु और प्रयोजन, अशुद्धि-शोधन, शब्द-रचना, शब्द-भेद, हिन्दी की रूप रचना, रूप-रचना, हिन्दी शब्द रचना, हिन्दी साहित्येतिहास दर्शन, भक्तिकालीन काव्यधाराएँ, भारतीय काव्यशास्त्र की परंपरा, भारतीय नवजागरण और स्वाधीनता आंदोलन, अन्य गद्य विधाएँ एवं प्रवासी साहित्य, निर्धारित उपन्यासों का तुलनात्मक अध्ययन, गोदान, हिन्दी कहानी का विकास, स्वातंत्र्योत्तर और नयी कहानी, हिन्दी निबंध का विकास, शुक्लोत्तर निबंध, द्विवेदी और शुक्ल युग के निबंध, हिन्दी की संवैधानिक स्थिति, आधुनिक भारतीय आर्यभाषाएँ और हिन्दी का उद्भव, हिन्दी भाषा प्रयोग के विविध रूप, रीतिकाल, जीवनी, द्विवेदी युग और छायावाद, रीति, वक्रोक्ति और औचित्य सिद्धान्त, शब्दशक्ति और ध्वनि सिद्धान्त, रस सिद्धान्त और साधारणीकरण, उत्तर आधुनिकतावाद, लोहिया दर्शन, हिन्दी उपन्यास का विकास, हिन्दी नवजागरण, अंबेडकर दर्शन, आदिकाल, प्रयोगवाद और नयी कविता, छायावादी काव्य: प्रसाद और निराला, प्रगतिवाद से समकालीन कविता, निर्गुण भक्ति काव्य, द्विवेदीयुगीन काव्य, रीतिकालीन काव्य, आरंभिक हिन्दी उपन्यास, स्वातंत्र्योत्तर उपन्यास, आत्मकथा, स्वाधीनता-पूर्व प्रेमचंदोत्तर उपन्यास, निर्धारित कहानियों का तुलनात्मक अध्ययन, साठोत्तरी नाटक, प्रसाद और प्रसादोत्तर युग के नाटक, भारतेन्दु युगीन नाटक, स्वातंत्र्योत्तर नाटक, भारतेन्दु युगीन निबंध, संस्मरण और रेखाचित्र, व्यंग्य, एक साहित्यिक की डायरी, संस्कृति के चार अध्याय, सगुण भक्ति काव्य, हिन्दी नाटक, एकांकी और रंगमंच, आधुनिक गद्य और हिन्दी नवजागरण, अलंकार सिद्धान्त, हिन्दी आलोचना का विकास, भक्ति आंदोलन, कल्पना, बिम्ब, प्रतीक, मिथक और फंतासी, नयी कविता का विस्तार और साठोत्तरी कविता, उत्तर-छायावादी और प्रगतिवादी काव्य, काव्यगुण और काव्यदोष, प्लेटो, अरस्तू और पाश्चात्य परंपरा, मार्क्सवाद, स्वच्छन्दतावादी काव्यशास्त्र, आधुनिक पाश्चात्य आलोचना, भाषा और भाषा परिवार, देवनागरी लिपि
  4. Paper 2 | General Studies: State Wise GK, Polity, Geography, History, GK- Current Affairs
  5. Paper 1 | Programming Language: Language Design, C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, OOPS with C++
  6. Paper 1 | Database Management Systems: 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, ORDBMS, NoSQL
  7. Paper 1 | Cyber Security: Society, Law & Ethics, Cyber Threats and Malware Attacks, Role of Internet and Web Services, Security in Mobile and Wireless Computing, Electronic Data Interchange and E-Commerce, Physical Security and Cryptography Basics, Intrusion Detection Systems (IDS), Cyber Safety and Security, Ethical Hacking
  8. Paper 1 | Computer Organization and Architecture: Basics of COA, Programming the Basic Computer, Cache Memory Organization, Input Output Organisation, Instr Formats & Modes, Register Transfer and Microoperations, Control Unit Design
  9. Paper 1 | Computer Networks: 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
  10. Paper 1 | Design and Analysis of Algorithms: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Advanced Algorithms
  11. Paper 1 | Data Structures: Introduction to DS, Array, Linked List, Stack, Queue, Tree, Graphs, Hashing
  12. Paper 1 | Discrete Structures and Theory of Logic: Permutation and Combination, Set Theory, Relations, Functions, Propositional and Predicate Logic, Graph Theory, Group Theory
  13. Paper 1 | Software Project Management: Software Project Management
  14. Paper 2 | Operating Systems: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management, Unix OS, Linux OS, Security
  15. 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, Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Pushdown Automata & CFG, Complexity Theory
  16. Paper 2 | Artificial Intelligence & High Performance Computing: Approaches to AI, Search Algorithms, Game Playing, Knowledge Representation, Planning, Multi Agent Systems, Natural Language Processing, Emerging Tech Trends
  17. Paper 2 | Image Processing: Digital Image Fundamentals, Image Enhancement, Image Restoration, Color Image Processing, Image Compression
  18. Paper 2 | Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
  19. Paper 2 | Computer Graphics: Basics of Computer Graphics, 2-D Geometrical Transforms and Viewing, 3-D Object Representation, Geometric Transformations and Viewing
  20. Paper 2 | Web Technologies: Website, Browser & Services, Internet Fundamentals, Web Design & Development, Protocols & Services, Web Publishing & Hosting, Server Side & Security, Emerging Technologies, HTML Basics, JavaScript-Basics, Java
  21. Paper 2 | Soft Computing: Fuzzy Sets, Artificial Neural Networks, Genetic Algorithms
  22. Paper 2 | Distributed System: Distributed Systems
  23. UPPSC Live Class Recordings: UPPSC Polytechnic Lecturer 2025 (CS)
  24. Previous Year Papers:
  25. Mock Test:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This lecture introduces threaded binary trees, a data structure that replaces NULL pointers with special links called threads to enable tree traversal without recursion or an auxiliary stack. The instructor defines the concept, distinguishes between single-threaded and double-threaded variants, and demonstrates how left and right pointers are repurposed to point to inorder predecessors or successors. A worked example uses a binary search tree with nodes 1, 2, 3, 5, and 7 (later expanded to a larger tree with values like 10, 8, 30, 4, 9, etc.) to show how NULL pointers are identified and replaced with thread links. The inorder traversal sequence 5, 8, 29, 4, 10, 9, 30, 41, 16, 52 is written on screen to illustrate predecessor and successor relationships. The instructor highlights specific nodes (e.g., 5, 4, 29, 8) and draws arrows to show how traversal proceeds from a node's right child or its inorder successor. The final segment demonstrates the complete inorder traversal of the threaded tree, showing how threads allow sequential access to all nodes without backtracking or stack operations.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The lecture opens with the definition of a Threaded Binary Tree on screen: 'A Threaded Binary Tree is a binary tree in which NULL pointers are replaced with special links (threads) to make traversal easier.' The stated purpose is 'To perform tree traversal without using recursion or stack.' Two types are introduced: Single Threaded Binary Tree (with subtypes Left-Threaded, where the left NULL pointer points to the Inorder Predecessor, and Right-Threaded, described as 'Most Common,' where the right NULL pointer points to the Inorder Successor) and Double Threaded Binary Tree. The instructor begins drawing a node structure with fields labeled 'Left Child Add.', 'Data', and 'Right Child Add.'

  2. 2:00 – 5:00 02:00-05:00

    The instructor draws a binary tree with nodes 1, 2, 3, 5, and 7, then expands individual nodes to show their internal three-field structure. Node 5 is expanded to display 'NULL, Data, 7000' and node 7 shows 'NULL, 7, null,' illustrating how NULL pointers appear in an unthreaded tree. A table format is used to show the left child address, data, and right child address for each node. The instructor then draws a more complete binary tree structure with colored boxes representing node fields and arrows indicating pointer directions, annotating nodes with inorder predecessor and successor threads to demonstrate the double-threaded variant.

  3. 5:00 – 10:00 05:00-10:00

    A larger binary tree is displayed with three-field nodes annotated with specific values: the root shows '100 10 300,' its left child shows '400 8 500,' and the right child shows '600 30 700.' Leaf nodes display values like 'NULL 5 NULL' and '800 4 NULL.' At the bottom, an inorder traversal sequence is written: '5 8 29 4 10 9 30 41 16 52.' The instructor circles the leftmost node (value 5) and draws a horizontal line under it to indicate its NULL pointers. The words 'Predecessor' and 'Successor' are written with arrows pointing to the inorder sequence, establishing that threads will link each node to its adjacent nodes in this traversal order.

  4. 10:00 – 14:50 10:00-14:50

    The instructor demonstrates the threading process by circling specific values in nodes and connecting them to their positions in the inorder sequence. The value 4 is circled with its null right child highlighted, and a line connects it to the inorder sequence. The value 29 is circled in both the tree and the traversal list, as are values 8 and 5. Green brackets are drawn under several nodes to indicate value ranges. In the final segment, arrows are drawn between nodes to represent successor pointers: an arrow from node 41 points to its successor 16, and an arrow from node 52 points to NULL. The inorder traversal sequence is updated step-by-step at the bottom, progressing through '5 8 29 4 10 9 30 41 16 52 NULL,' demonstrating how threads enable sequential traversal without recursion or a stack.

The lecture progresses from definition to demonstration. First, the core concept is established: NULL pointers in a binary tree are replaced with threads that point to inorder predecessors or successors, eliminating the need for recursion or a stack during traversal. Second, the two main variants are distinguished: single-threaded trees (left or right) and double-threaded trees, with the node structure shown as having three fields (left pointer, data, right pointer). Third, a concrete example is built incrementally: starting with a small tree (nodes 1-7), the instructor expands to show internal node structure, then moves to a larger tree with specific pointer values (e.g., '100 10 300' at the root). The inorder traversal sequence is written out to make predecessor-successor relationships explicit. Finally, the threading process is demonstrated by highlighting NULL pointers and drawing arrows to show how each node's thread links it to its inorder neighbor. The key pedagogical move is connecting the abstract definition (NULL replaced by thread) to a concrete visual example where students can trace the traversal path using only the threads, confirming that no stack or recursion is needed. The sequence 5-8-29-4-10-9-30-41-16-52 serves as the reference for all predecessor and successor links throughout the demonstration.

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