Sect 8. Tree

CONCEPTS
  
  Tree, root, subtree, ordered tree
  Terminology: parent, child, ancestor, descendant, sibling, branch, leaf
  Binary tree, left/right child, full,
  Level, height
  Binary search tree, insertion, deletion
  Decision tree
  Huffman codes
  Traversals: preorder, postorder, inorder
  Expression notation: infix, Polish, evaluation

NOTATION

SKILLS
  
  1. Identify concepts in a context
     E.g., tell children, ancestors, etc, of a node in a tree
     E.g., tell whether a traversal is pre/post/inorder
  2. Manipulate trees
     E.g., transform tree into binary and vice versa
     E.g., insert/remove nodes in binary search trees
  3. Use trees in problems
     E.g., build decision trees, reason about complexity
     E.g., build Huffman codes of language
     E.g., transform infix to Polish notations and vice versa
     E.r., evaluate Polish notation expressions
       
SOURCES

  Tutorialspoint: Introduction to trees
  https://www.tutorialspoint.com/discrete_mathematics/introduction_to_trees.htm

  Wikipedia: Binary expression tree
  https://en.wikipedia.org/wiki/Binary_expression_tree

  *** Recommended ***
  Youtube: Binary Search Trees (BSTs) - Insert and Remove Explained, by Colleen Lewis
  https://www.youtube.com/watch?v=wcIRPqTR3Kc

  Youtube: Binary tree traversal, by AlgoGeeks
  https://www.youtube.com/watch?v=GsrPQ32sPTI
  Youtube: Binary Tree Traversal (Preorder, Inorder, Postorder) by Introduction to Data Structures
  https://www.youtube.com/watch?v=-aIcPlIQ_MI

  Youtube: Finding the heavier ball, Khan Academy (decision tree)
  https://www.youtube.com/watch?v=0Jgow5x09qw

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  *** Recommended ***   
  Lerma, chap 7 

  LLM, sect 6.1 and 6.4

  ADS, chap 10

  BDS, Important concepts at the end of the section 6