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 "cells": [
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   "cell_type": "markdown",
   "id": "4708c5dc-a1e8-42e2-8702-ecea9513d54b",
   "metadata": {},
   "source": [
    "# a binary tree of leaves of letters"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "id": "906fc548-a2a5-411b-ad60-9e93e88bf7f5",
   "metadata": {},
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   "source": [
    "# http://syllabus.cs.manchester.ac.uk/ugt/2021/COMP26912/lab/ex5.html\n",
    "# https://web.stanford.edu/class/archive/cs/cs106x/cs106x.1174/assn/twentyOneQuestions.html\n",
    "# https://www.openbookproject.net/py4fun/animal/animal.html"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "id": "578e93f8-e04f-4b01-a482-ebc78cf2c103",
   "metadata": {},
   "outputs": [],
   "source": [
    "# each leaf stores a letter to be asked\n",
    "class letterLeaf:\n",
    "    def __init__(self,letter):\n",
    "        self.leftAlphabet = None\n",
    "        self.rightAlphabet = None\n",
    "        self.letter = letter\n",
    "        # try using a list structure to contain the words in this node? \n",
    "        self.words = []"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "id": "fa8e3d45-ea21-47e1-9a5a-256e5e7ebed1",
   "metadata": {},
   "outputs": [],
   "source": [
    "# tree traversals, here to print stuff \n",
    "def inorder(treeName):\n",
    "    if treeName:\n",
    "        inorder(treeName.leftAlphabet)\n",
    "        print(treeName.letter)\n",
    "        inorder(treeName.rightAlphabet)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "id": "0c75f820-46c4-46af-b5d9-b837cb055b55",
   "metadata": {},
   "outputs": [],
   "source": [
    "# printing tree utility \n",
    "# this segment is modified from Shubham Singh(SHUBHAMSINGH10)'s contribution \n",
    "\n",
    "# spacer\n",
    "COUNT = [10]\n",
    "\n",
    "# print a flat lying tree\n",
    "# speculation： this is a recursion that prints the right leaf until there is nothing left\n",
    "def print2DUtil_flat(root, space) :\n",
    "    # Base case\n",
    "    if (root == None) :\n",
    "        return\n",
    "    # Increase distance between levels\n",
    "    space += COUNT[0]\n",
    "    # Process right leaf/branch/child first\n",
    "    print2DUtil_flat(root.rightAlphabet, space)\n",
    "    print()\n",
    "    for i in range(COUNT[0], space):\n",
    "        print(end = \" \")\n",
    "    print(root.letter)\n",
    "    # Process left child\n",
    "    print2DUtil_flat(root.leftAlphabet, space)\n",
    "\n",
    "    # Wrapper over print2DUtil()\n",
    "def print2D(root) :\n",
    "    #Pass initial space count as 0\n",
    "    print(\"here is a tree that's laying on the ground: \")\n",
    "    print2DUtil_flat(root, 0)\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "id": "5f27d6d6-3019-4714-98d0-9650f1e087bb",
   "metadata": {},
   "outputs": [],
   "source": [
    "# utility to read the first letter of the input word \n",
    "# press enter key, otherwise notebook will be pending\n",
    "def grepFirstLetter():\n",
    "    word = input()\n",
    "    firstLetter = word[0]\n",
    "    return firstLetter\n",
    "    #print(\"the letter starts with : {}, and will be inserted under the {} leaf\".format(firstLetter, firstLetter))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "id": "11081ff6-0295-4329-885c-6e6ddfddfcbf",
   "metadata": {},
   "outputs": [],
   "source": [
    "def insertLeaf(root,firstLetter):\n",
    "    #create new leaf \n",
    "    letterLeaf(firstLetter)\n",
    "    # python pointer implementation\n",
    "    # a root pointer \n",
    "    x = root\n",
    "    # pointer y maintains the trailing\n",
    "    # pointer of x\n",
    "    y = None\n",
    "    # traversal \n",
    "    # while x != none means the pointer can keep traversing\n",
    "    while(x != None):\n",
    "        y = x #trailing pointer points to x \n",
    "        if (firstLetter < x.letter):\n",
    "            x = x.leftAlphabet\n",
    "        else:\n",
    "            x = x.rightAlphabet\n",
    "    # insert leaf at root when tree is empty \n",
    "    if (y == None):\n",
    "        y = letterLeaf \n",
    "    # do string comparison, insert at left side of the alphabetTree \n",
    "    elif (firstLetter < x.letter):\n",
    "        x.leftAlphabet = letterLeaf\n",
    "    # insert at right side of the alphabetTree\n",
    "    else:\n",
    "        x.rightAlphabet = letterLeaf\n",
    "    return y\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "id": "22301756-70e0-4ff7-b9bb-4f59c458058b",
   "metadata": {},
   "outputs": [],
   "source": [
    "# print binary tree in 2D copied from sample program\n",
    "COUNT = [10]\n",
    "def print2DUtil(root, space) :\n",
    "\n",
    "    # Base case\n",
    "    if (root == None) :\n",
    "        return\n",
    "\n",
    "    # Increase distance between levels\n",
    "    space += COUNT[0]\n",
    "\n",
    "    # Process right child first\n",
    "    print2DUtil(root.rightAlphabet, space)\n",
    "\n",
    "    # Print current node after space\n",
    "    # count\n",
    "    print()\n",
    "    for i in range(COUNT[0], space):\n",
    "        print(end = \" \")\n",
    "    print(root.letter)\n",
    "\n",
    "    # Process left child\n",
    "    print2DUtil(root.leftAlphabet, space)\n",
    "\n",
    "# Wrapper over print2DUtil()\n",
    "def print2D(root) :\n",
    "    \n",
    "    # space=[0]\n",
    "    # Pass initial space count as 0\n",
    "    print2DUtil(root, 0)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "id": "883373d0-cccc-4497-b9ff-af45670cb1ce",
   "metadata": {},
   "outputs": [],
   "source": [
    "# A utility function to insert a new\n",
    "# Node with given key in BST\n",
    "def insert(root, letter):\n",
    "\n",
    "    # Create a new Node containing\n",
    "    # the new element\n",
    "    newleaf = letterLeaf(letter)\n",
    "\n",
    "    # Pointer to start traversing from root\n",
    "    # and traverses downward path to search\n",
    "    # where the new node to be inserted\n",
    "    x = root\n",
    "\n",
    "    # Pointer y maintains the trailing\n",
    "    # pointer of x\n",
    "    y = None\n",
    "\n",
    "    while (x != None):\n",
    "        y = x\n",
    "        if (letter < x.letter):\n",
    "            x = x.leftAlphabet\n",
    "        else:\n",
    "            x = x.rightAlphabet\n",
    "    \n",
    "    # If the root is None i.e the tree is\n",
    "    # empty. The new node is the root node\n",
    "    if (y == None):\n",
    "        y = newleaf\n",
    "\n",
    "    # If the new key is less then the leaf node key\n",
    "    # Assign the new node to be its left child\n",
    "    elif (letter < y.letter):\n",
    "        y.leftAlphabet = newleaf\n",
    "\n",
    "    # else assign the new node its\n",
    "    # right child\n",
    "    else:\n",
    "        y.rightAlphabet = newleaf\n",
    "\n",
    "    # Returns the pointer where the\n",
    "    # new node is inserted\n",
    "    return y\n",
    "\n",
    "# A utility function to do inorder\n",
    "# traversal of BST"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "id": "0f0bed93-2858-471b-b827-35f66da519b8",
   "metadata": {},
   "outputs": [],
   "source": [
    "def Inorder(root) :\n",
    "\n",
    "    if (root == None) :\n",
    "        return\n",
    "    else:\n",
    "        Inorder(root.leftAlphabet)\n",
    "        print( root.letter, end = \" \" )\n",
    "        Inorder(root.rightAlphabet)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "id": "e1884b95-8b53-49d6-b56c-a7226f14937e",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'w', 'x', 'y', 'z']\n",
      "\n",
      "                    z\n",
      "\n",
      "          y\n",
      "\n",
      "                              x\n",
      "\n",
      "                    w\n",
      "\n",
      "v\n",
      "\n",
      "                                        u\n",
      "\n",
      "                              t\n",
      "\n",
      "                    s\n",
      "\n",
      "                                        r\n",
      "\n",
      "                              q\n",
      "\n",
      "                                        p\n",
      "\n",
      "                                                  o\n",
      "\n",
      "          n\n",
      "\n",
      "                                        m\n",
      "\n",
      "                              l\n",
      "\n",
      "                                                  k\n",
      "\n",
      "                                        j\n",
      "\n",
      "                    i\n",
      "\n",
      "                              h\n",
      "\n",
      "                                                                      g\n",
      "\n",
      "                                                            f\n",
      "\n",
      "                                                                      e\n",
      "\n",
      "                                                  d\n",
      "\n",
      "                                                                      c\n",
      "\n",
      "                                                            b\n",
      "\n",
      "                                        a\n"
     ]
    }
   ],
   "source": [
    "#Driver Code\n",
    "import random\n",
    "#if __name__ == '__main__':\n",
    "\n",
    "alphabet = [\"a\",\"b\",\"c\",\"d\",\"e\",\"f\",\"g\",\"h\",\"i\",\"j\",\"k\",\"l\",\"m\",\"n\",\"o\",\"p\",\"q\",\"r\",\"s\",\"t\",\"u\",\"v\",\"w\",\"x\",\"y\",\"z\"]\n",
    "root = None\n",
    "# pick a random letter in the alphabet\n",
    "random_letter = random.choice(alphabet)\n",
    "#print(random_letter)\n",
    "#insert it into the tree, insert the first one \n",
    "root = insert(root, random_letter)\n",
    "# remove that letter from list\n",
    "alphabet.remove(random_letter)\n",
    "print(alphabet)\n",
    "len_list = (len(alphabet))\n",
    "#print(len_list)\n",
    "while len_list > 0:\n",
    "    random_letter = random.choice(alphabet)\n",
    "    insert(root,random_letter)\n",
    "    alphabet.remove(random_letter)\n",
    "    #print(\"inserting and removing letter {} \".format(random_letter))\n",
    "    len_list -= 1\n",
    "# keep inserting until the list is empty \n",
    "# print tree \n",
    "print2D(root)\n",
    "# can try multiple times for different tree configurations"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 329,
   "id": "d222d70f-2771-45be-9ac1-7ac579a242cb",
   "metadata": {},
   "outputs": [],
   "source": [
    "# print a vertical standing tree \n",
    "# https://www.geeksforgeeks.org/print-level-order-traversal-line-line/\n",
    "# https://www.geeksforgeeks.org/level-order-tree-traversal/"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 323,
   "id": "39d68b3e-064e-4ed6-b10d-c7250a7034e3",
   "metadata": {},
   "outputs": [],
   "source": [
    "# a morse code tree\n",
    "# https://www.101computing.net/morse-code-using-a-binary-tree/"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "f7205015-dd4b-48bf-94c4-be0f96d8988a",
   "metadata": {},
   "outputs": [],
   "source": [
    "#firstLetter = grepFirstLetter()\n",
    "#print(firstLetter)"
   ]
  }
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