Tree traversal Practice Question

Duration: 2 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.

This educational video segment focuses on solving a binary tree traversal problem commonly found in computer science exams. The instructor presents a specific question asking for the post-order traversal given the in-order sequence "d b e a f c g" and the pre-order sequence "a b d e c f g". He begins by identifying the root of the tree from the first element of the pre-order traversal, which is 'a'. He then locates 'a' in the in-order sequence to divide the tree into left and right subtrees. The left subtree contains nodes "d b e" and the right subtree contains "f c g". He proceeds to recursively apply this logic to construct the full tree structure on the whiteboard. Finally, he performs a post-order traversal (Left-Right-Root) on the constructed tree to determine the final sequence, writing it down for verification against the multiple-choice options. He carefully checks each node's position to ensure the traversal order is correct.

Chapters

  1. 0:00 – 1:36 00:00-01:36

    The video opens with the problem statement displayed on screen, showing in-order "d b e a f c g" and pre-order "a b d e c f g" sequences. The instructor identifies 'a' as the root node from the pre-order list and marks it in the in-order list to split nodes into left "d b e" and right "f c g" groups. He explains that 'b' is the root of the left subtree and 'c' is the root of the right subtree. He draws the tree structure on the whiteboard, placing 'a' at the top with 'b' and 'c' as children, and fills in leaves 'd', 'e', 'f', and 'g'. Finally, he writes the post-order sequence "d e b f g c a" at the bottom and underlines option (d), noting a discrepancy between his written result and the printed options.

The video effectively demonstrates the recursive algorithm for reconstructing a binary tree from its traversals. By alternating between pre-order (to find roots) and in-order (to define subtrees), one can uniquely determine the tree structure. The final post-order traversal is simply the reverse of the construction process, visiting children before parents. This method is crucial for understanding tree data structures and their properties in computer science exams, highlighting the relationship between different traversal orders. It shows how a single tree can be represented by multiple sequences.

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