149 lines
4.5 KiB
Plaintext
149 lines
4.5 KiB
Plaintext
{
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"cells": [
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"# Binary Search Tree\n",
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"**Constructor** sets three attributes: data, left subtree and right subtree. \n",
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"**Insert** inserts a new subtree into the proper location. \n",
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"**Find** finds a value. If value not found, returns False. \n",
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"**Get_size** returns the number of nodes in the tree (excluding None nodes). \n",
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"**Preorder** prints a preorder traversal of the tree. \n",
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"**Inorder** prints an inorder traversal of the tree."
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]
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},
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{
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"cell_type": "code",
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"execution_count": 69,
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"metadata": {},
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"outputs": [],
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"source": [
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"class Tree:\n",
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" def __init__(self, data, left=None, right=None):\n",
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" self.data = data\n",
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" self.left = left\n",
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" self.right = right\n",
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" def insert(self, data):\n",
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" if self.data == data:\n",
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" return False # duplicate value\n",
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" elif self.data > data:\n",
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" if self.left is not None:\n",
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" return self.left.insert(data)\n",
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" else:\n",
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" self.left = Tree(data)\n",
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" return True\n",
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" else:\n",
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" if self.right is not None:\n",
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" return self.right.insert(data)\n",
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" else:\n",
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" self.right = Tree(data)\n",
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" return True\n",
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" def find(self, data):\n",
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" if self.data == data:\n",
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" return data\n",
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" elif self.data > data:\n",
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" if self.left is None:\n",
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" return False\n",
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" else:\n",
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" return self.left.find(data)\n",
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" elif self.data < data:\n",
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" if self.right is None:\n",
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" return False\n",
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" else:\n",
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" return self.right.find(data)\n",
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" def get_size(self):\n",
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" if self.left is not None and self.right is not None:\n",
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" return 1 + self.left.get_size() + self.right.get_size()\n",
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" elif self.left:\n",
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" return 1 + self.left.get_size()\n",
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" elif self.right:\n",
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" return 1 + self.right.get_size()\n",
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" else:\n",
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" return 1\n",
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" def preorder(self):\n",
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" if self is not None:\n",
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" print (self.data, end=' ')\n",
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" if self.left is not None:\n",
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" self.left.preorder()\n",
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" if self.right:\n",
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" self.right.preorder()\n",
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" def inorder(self):\n",
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" if self is not None:\n",
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" if self.left is not None:\n",
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" self.left.inorder()\n",
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" print (self.data, end=' ')\n",
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" if self.right is not None:\n",
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" self.right.inorder()\n"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"### Test Code\n",
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"We create a new tree, insert one value, insert a whole list of values, find all values from 1 to 15 (False for 0, 5 and 8 shows that those values are not in the tree), print the size of the tree, print preorder and postorder traversals."
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]
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},
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{
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"cell_type": "code",
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"execution_count": 70,
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"metadata": {},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"False 1 2 3 4 False 6 7 False 9 10 11 12 13 14 15 \n",
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" 13\n",
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"7 2 1 3 6 4 9 15 10 12 11 13 14 \n",
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"1 2 3 4 6 7 9 10 11 12 13 14 15 \n"
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]
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}
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],
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"source": [
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"tree = Tree(7)\n",
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"tree.insert(9)\n",
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"for i in [15, 10, 2, 12, 3, 1, 13, 6, 11, 4, 14, 9]:\n",
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" tree.insert(i)\n",
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"for i in range(16):\n",
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" print(tree.find(i), end=' ')\n",
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"print('\\n', tree.get_size())\n",
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"\n",
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"tree.preorder()\n",
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"print()\n",
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"tree.inorder()\n",
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"print()"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": []
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}
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],
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"metadata": {
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"kernelspec": {
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"display_name": "Python 3",
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"language": "python",
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"name": "python3"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython3",
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"version": "3.7.0"
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"nbformat": 4,
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