Tree traversal Practice Question
Duration: 1 min
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Module outline
- General Intelligence & Reasoning: Analogy, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Blood Relations, Directions (Direction Test), Ranking, Order and Sequence, Logical Sequence Of Words, Syllogisms, Venn Diagram, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Selection Decision Table (Decision Making), Data Sufficiency, Puzzle Solving (Puzzles), Data Arrangement, Cubes & Dices, Calendar, Clock, Arithmetic, Number System, HCF LCM, Verbal Analogy (Word Based Analogy), Visual Recognition and Figure Completion, Paper Folding and Cutting, Transformation of Shapes, Clocks and Calendars, Direction Sense, Cubes and Dice, Patterns in Two-Dimensional Figures, Seating Arrangements, Analogy and Classification, Logical Deduction and Induction, Alphabet and Word Tests, Mathematical Operations, Series Completion, Simplification and Approximation, Coding and Decoding, Numerical Reasoning, Assembling and Grouping of Shapes, Three-Dimensional Patterns and Visualization, Vocabulary, Number System, Averages, Mixtures and Alligation, Simple and Compound Interest, Percentages, Algebra, Speed, Time and Distance, Seating and Arrangement Puzzles, Traverse Surveying, Order, Ranking and Sequence, Constraint Puzzles, Syllogisms and Venn Diagrams, Reading Comprehension, Critical Reasoning, Permutations and Combinations, Narrative Sequencing, Project Monitoring, Resources and Safety, Profit, Loss and Discount, Ratio and Proportion, Time and Work, Mensuration, Data Interpretation, Powers, Surds and Logarithms, Sequences and Series, Articles and Determiners, Sentence Completion, Data Sufficiency, Blood Relations, Simple Interest and Compound Interest, Mixture and Alligation, Sequence and Series (Series), Speed Time and Distance, Algebra, Profit and Loss, Powers and Exponents (Surds and Indices), Permutation and Combination
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- Full Length Mock Tests:
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AI summary & chapters
AI Summary
An AI-generated summary of this video lecture.
The video presents a multiple-choice question regarding binary tree traversals found in computer science data structures. The question asks which pair of traversals is insufficient to reconstruct a unique binary tree. The options provided are (A) Preorder and Inorder, (B) Preorder and Post order, (C) Inorder and Post order, and (D) level order and post order. The instructor analyzes each option to determine sufficiency for tree construction.
Chapters
0:00 – 0:52 00:00-00:52
The instructor starts by reading the question on the screen: 'Which of the following pairs of traversals is not sufficient to build a binary tree from the given traversals?' He systematically evaluates the options. He places checkmarks next to options (A), (C), and (D), indicating that these pairs are sufficient to construct a unique binary tree. He then circles option (B) 'Preorder and Post order' as the correct answer to the question. To illustrate why this pair is insufficient, he draws a simple tree structure with a root node and a single child node. He explains that if a node has only one child, the Preorder and Postorder traversals will be identical regardless of whether that child is a left child or a right child. For instance, if the root is 'A' and the child is 'B', Preorder is A, B and Postorder is B, A. This ambiguity means the tree structure cannot be uniquely determined. He emphasizes that without Inorder traversal, the relative position of nodes (left vs right) cannot be established when a node has only one child.
The lecture concludes that while Inorder combined with either Preorder or Postorder allows for unique tree reconstruction, Preorder and Postorder alone lack the necessary information to distinguish between left and right children for nodes with a single child. This is a critical concept for understanding tree reconstruction algorithms.

