update chapters with external resrouces

Author: rambasnet

markdowns/Ch23-Trees.md

@@ -1,8 +1,17 @@
 # Trees
 <a href="https://colab.research.google.com/github/rambasnet/Python-Fundamentals/blob/master/notebooks/Ch23-Trees.ipynb" target="_parent"><img src="https://colab.research.google.com/assets/colab-badge.svg" alt="Open In Colab"/></a>
 
-http://openbookproject.net/thinkcs/python/english3e/trees.html
-- like linked lists, trees are made up of nodes
+## External Resources
+- Think Python - [http://openbookproject.net/thinkcs/python/english3e/trees.html](http://openbookproject.net/thinkcs/python/english3e/trees.html)
+
+
+## Overview
+
+- like linked lists, trees are made up of nodes or objects that contain data and references to other nodes
+- unlike linked lists, trees can have multiple references to other nodes
+- trees are hierarchical data structures that are used to represent relationships between data items
+- trees are widely used in computer science for various applications such as searching, sorting, and organizing data
+- common types of trees include binary trees, binary search trees, AVL trees, and B-trees, etc.
 
 ## Binary Tree
  - is a commonly used tree in which each node contains a reference to atmost two other nodes (possibly None)
@@ -11,6 +20,11 @@ http://openbookproject.net/thinkcs/python/english3e/trees.html
 - like linked lists, trees are recursive data structures that are defined recursively:
     1. the empty tree, represented by None, or
     2. a node that contains a data and two tree references (left and right subtree)
+- the topmost node in the tree is called the root node
+- nodes with no children are called leaf nodes
+- nodes that are not leaf nodes are called internal nodes
+- the height of a tree is the length of the longest path from the root to a leaf
+- trees can be traversed in different ways such as inorder, preorder, and postorder traversal
 
 ## Building trees
 - similar to building linked-list
@@ -60,7 +74,15 @@ print(tree1)
 
 
 ## traversing tree
+
 - natural way to traverse a tree is recursively!
+- for each node, visit the node and then recursively visit its left and right subtrees
+- three common ways to traverse a binary tree:
+    - inorder traversal
+    - preorder traversal
+    - postorder traversal
+- each traversal visits the nodes in a different order and is useful for different applications
+
 
 
 ```python
@@ -116,13 +138,15 @@ expression = Tree('+', Tree(1), Tree('*', Tree(2), Tree(3)))
 ```
 
 ### pre-order tree traversal
+
 - contents of the root appear before the contents of the children
 - recursive algorithm:
     - visit the node
-    - visit left subtree
+    - visit left subtree 
     - visit right subtree
 
 
+
 ```python
 def preorder(tree):
     if not tree:

notebooks/Ch04-Conditionals.ipynb

@@ -18,7 +18,7 @@
     "## External Resources\n",
     "\n",
     "- YouTube Video - [https://youtu.be/59dZxyidO0k](https://youtu.be/59dZxyidO0k)\n",
-    "- YouTube Podcast - [https://youtu.be/cSypvtZ3wCQ](https://youtu.be/cSypvtZ3wCQ)\n",
+    "- YouTube Podcast - [https://youtu.be/uAEaTBj8amY](https://youtu.be/uAEaTBj8amY)\n",
     "- NotebookLM learning resources - [https://notebooklm.google.com/notebook/63f84517-0108-46f3-95ae-5b88a91dc288](https://notebooklm.google.com/notebook/63f84517-0108-46f3-95ae-5b88a91dc288)\n",
     "\n",
     "## Conditional/Logical Structures\n",

notebooks/Ch09-2-Built-in-DataStructures.ipynb

@@ -12,8 +12,12 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "- all builtin functions are listed here with examples: https://docs.python.org/3/library/functions.html\n",
     "\n",
+    "## External Resources\n",
+    "- all builtin functions are listed here with examples: https://docs.python.org/3/library/functions.html\n",
+    "- YouTube Video - [https://youtu.be/gINs_P8iyI8](https://youtu.be/gINs_P8iyI8)\n",
+    "- YouTube Podcast - [https://youtu.be/4uth7ylvu9k](https://youtu.be/4uth7ylvu9k)\n",
+    "- NotebookLM learning resources - [https://notebooklm.google.com/notebook/444b976d-bdd4-4668-8f90-66c0b9866f9e](https://notebooklm.google.com/notebook/444b976d-bdd4-4668-8f90-66c0b9866f9e)\n",
     "\n",
     "## zip( )\n",
     "- built-in zip class can help us quickly create list of tuples and then a dictionary"

notebooks/Ch21-Stacks.ipynb

@@ -7,7 +7,12 @@
     "# Stacks\n",
     "<a href=\"https://colab.research.google.com/github/rambasnet/Python-Fundamentals/blob/master/notebooks/Ch21-Stacks.ipynb\" target=\"_parent\"><img src=\"https://colab.research.google.com/assets/colab-badge.svg\" alt=\"Open In Colab\"/></a>\n",
     "\n",
-    "http://openbookproject.net/thinkcs/python/english3e/stacks.html\n",
+    "## External Resources\n",
+    "\n",
+    "- Think Python - [http://openbookproject.net/thinkcs/python/english3e/stacks.html](http://openbookproject.net/thinkcs/python/english3e/stacks.html)\n",
+    "- YouTube Video - [https://youtu.be/UXjpI8zFBjo](https://youtu.be/UXjpI8zFBjo)\n",
+    "- YouTube Podcast - [https://youtu.be/nuro24feUMc](https://youtu.be/nuro24feUMc)\n",
+    "- NotebookLM learning resources - [https://notebooklm.google.com/notebook/1c\n",
     "\n",
     "- container adapters or abstract data type (ADT) that may use list or linked-list as containers to hold data\n",
     "- specifically designed to operate as a LIFO (last-in-first-out) or FILO (first-in-last-out) data structure \n",

notebooks/Ch22-Queues.ipynb

@@ -7,12 +7,19 @@
     "# Queues\n",
     "<a href=\"https://colab.research.google.com/github/rambasnet/Python-Fundamentals/blob/master/notebooks/Ch22-Queues.ipynb\" target=\"_parent\"><img src=\"https://colab.research.google.com/assets/colab-badge.svg\" alt=\"Open In Colab\"/></a>\n",
     "\n",
-    "http://openbookproject.net/thinkcs/python/english3e/queues.html\n",
+    "## External Resources\n",
+    "- Think Python - [http://openbookproject.net/thinkcs/python/english3e/queues.html](http://openbookproject.net/thinkcs/python/english3e/queues.html)\n",
+    "- YouTube Video - [https://youtu.be/V1aQfaHWGNQ](https://youtu.be/V1aQfaHWGNQ)\n",
+    "- YouTube Podcast - [https://youtu.be/RVmdAAHpqwA](https://youtu.be/RVmdAAHpqwA)\n",
+    "- NotebookLM learning resources - [https://notebooklm.google.com/notebook/3fa6e2\n",
+    "\n",
+    "\n",
+    "## Overview\n",
     "- another container adapter or ADT, which is typically a first-in-first-out (FIFO) data structure\n",
     "- mimics real-world queue/line of people waiting for something\n",
     "- rule that determines who goes next is called the queuing policy\n",
     "- the most general queuing policy is priority queuing, in which each item/person is assigned a priority and the element with highest priority goes first, regardless of the order of the arrival\n",
-    "- built-in alternative - deque: https://docs.python.org/3/library/collections.html#collections.deque"
+    "- built-in alternative - deque: https://docs.python.org/3/library/collections.html#collections.deque\n"
    ]
   },
   {

notebooks/Ch23-Trees.ipynb

@@ -7,16 +7,32 @@
     "# Trees\n",
     "<a href=\"https://colab.research.google.com/github/rambasnet/Python-Fundamentals/blob/master/notebooks/Ch23-Trees.ipynb\" target=\"_parent\"><img src=\"https://colab.research.google.com/assets/colab-badge.svg\" alt=\"Open In Colab\"/></a>\n",
     "\n",
-    "http://openbookproject.net/thinkcs/python/english3e/trees.html\n",
-    "- like linked lists, trees are made up of nodes\n",
+    "## External Resources\n",
+    "- Think Python - [http://openbookproject.net/thinkcs/python/english3e/trees.html](http://openbookproject.net/thinkcs/python/english3e/trees.html)\n",
+    "- YouTube Video - [https://youtu.be/8ZUsDn98hNY](https://youtu.be/8ZUsDn98hNY)\n",
+    "- YouTube Podcast - [https://youtu.be/wj0s8OIzcX4](https://youtu.be/wj0s8OIzcX4)\n",
+    "- NotebookLM learning resources - [https://notebooklm.google.com/notebook/eb7913fe-030f-43aa-a2f3-1c15cabac10c](https://notebooklm.google.com/notebook/eb7913fe-030f-43aa-a2f3-1c15cabac10c)\n",
+    "\n",
+    "## Overview\n",
+    "\n",
+    "- like linked lists, trees are made up of nodes or objects that contain data and references to other nodes\n",
+    "- unlike linked lists, trees can have multiple references to other nodes\n",
+    "- trees are hierarchical data structures that are used to represent relationships between data items\n",
+    "- trees are widely used in computer science for various applications such as searching, sorting, and organizing data\n",
+    "- common types of trees include binary trees, binary search trees, AVL trees, and B-trees, etc.\n",
     "\n",
     "## Binary Tree\n",
     " - is a commonly used tree in which each node contains a reference to atmost two other nodes (possibly None)\n",
     "- these references are referred to as the left and right subtrees\n",
     "- like the node of linked list, each node also contains data/cargo\n",
     "- like linked lists, trees are recursive data structures that are defined recursively:\n",
     "    1. the empty tree, represented by None, or\n",
-    "    2. a node that contains a data and two tree references (left and right subtree)"
+    "    2. a node that contains a data and two tree references (left and right subtree)\n",
+    "- the topmost node in the tree is called the root node\n",
+    "- nodes with no children are called leaf nodes\n",
+    "- nodes that are not leaf nodes are called internal nodes\n",
+    "- the height of a tree is the length of the longest path from the root to a leaf\n",
+    "- trees can be traversed in different ways such as inorder, preorder, and postorder traversal"
    ]
   },
   {
@@ -111,7 +127,14 @@
    "metadata": {},
    "source": [
     "## traversing tree\n",
-    "- natural way to traverse a tree is recursively!"
+    "\n",
+    "- natural way to traverse a tree is recursively!\n",
+    "- for each node, visit the node and then recursively visit its left and right subtrees\n",
+    "- three common ways to traverse a binary tree:\n",
+    "    - inorder traversal\n",
+    "    - preorder traversal\n",
+    "    - postorder traversal\n",
+    "- each traversal visits the nodes in a different order and is useful for different applications\n"
    ]
   },
   {
@@ -201,11 +224,12 @@
    "metadata": {},
    "source": [
     "### pre-order tree traversal\n",
+    "\n",
     "- contents of the root appear before the contents of the children\n",
     "- recursive algorithm:\n",
     "    - visit the node\n",
-    "    - visit left subtree\n",
-    "    - visit right subtree"
+    "    - visit left subtree \n",
+    "    - visit right subtree\n"
    ]
   },
   {