interactive-coding-challenges/graphs_trees/binary_tree/binary_tree_challenge.ipynb
2015-07-18 00:55:33 -05:00

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"source": [
"<small><i>This notebook was prepared by Marco Guajardo. Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges).</i></small>"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Challenge Notebook"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Problem: Implement a binary search tree with insert, delete, different traversals & max/min node values\n",
"* [Constraints](#Constraints)\n",
"* [Test Cases](#Test-Cases)\n",
"* [Algorithm](#Algorithm)\n",
"* [Code](#Code)\n",
"* [Unit Test](#Unit-Test)\n",
"* [Solution Notebook](#Solution-Notebook)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Constraints\n",
"* Is this a binary tree?\n",
" * Yes\n",
"* Is the root set to None initially?\n",
" * Yes\n",
"* Do we care if the tree is balanced?\n",
" * No\n",
"* What do we return for the traversals?\n",
" * Return a list of the data in the desired order\n",
"* What type of data can the tree hold?\n",
" * Assume the tree only takes ints. In a realistic example, we'd use a hash table to convert other types to ints."
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Test Cases\n",
"\n",
"### Insert \n",
"\n",
"* Always start with the root\n",
"* If value is less than the root, go to the left child\n",
"* if value is more than the root, go to the right child\n",
"\n",
"\n",
"### Delete\n",
"\n",
"* Deleting a node from a binary tree is tricky. Make sure you arrange the tree correctly when deleting a node.\n",
"* Here are some basic [instructions](http://www.algolist.net/Data_structures/Binary_search_tree/Removal)\n",
"* If the value to delete isn't on the tree return False\n",
"\n",
"### Traverals \n",
"\n",
"* In order traversal -left, center, right\n",
"* Pre order traversal - center, left, right\n",
"* Post order traversal - left, right, center\n",
"* Return list for all traverals \n",
"\n",
"### Max & Min\n",
"* Find the max node in the binary search tree\n",
"* Find the min node in the binary search tree\n",
"\n",
"### treeIsEmpty\n",
"* check if the tree is empty\n",
"\n",
"\n",
"## Algorithm\n",
"\n",
"Refer to the [Solution Notebook](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/graphs_trees/binary_tree_implementation/binary_tree_solution.ipynb). If you are stuck and need a hint, the solution notebook's algorithm discussion might be a good place to start."
]
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{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Code"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"collapsed": true
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"outputs": [],
"source": [
"class Node (object):\n",
" def __init__ (self, data=None):\n",
" #TODO:implement me\n",
" pass\n",
" \n",
" def __str__ (self):\n",
" #TODO:implement me\n",
" pass"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"collapsed": true
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"outputs": [],
"source": [
"class BinaryTree (object):\n",
" def __init__ (self):\n",
" #TODO:implement me\n",
" pass\n",
" \n",
" def insert (self, newData):\n",
" #TODO:implement me\n",
" pass\n",
" \n",
" def delete (self, key):\n",
" #TODO:implement me\n",
" pass\n",
" \n",
" def maxNode (self):\n",
" #TODO:implement me\n",
" pass\n",
" \n",
" def minNode (self):\n",
" #TODO:implement me\n",
" pass\n",
" \n",
" def printPostOrder (self):\n",
" #TODO:implement me\n",
" pass\n",
" \n",
" def printPreOrder (self):\n",
" #TODO:implement me\n",
" pass\n",
" \n",
" def printInOrder (self):\n",
" #TODO:implement me\n",
" pass\n",
" \n",
" def treeIsEmpty (self):\n",
" #TODO: implement me\n",
" pass\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Unit Test"
]
},
{
"cell_type": "code",
"execution_count": 6,
"metadata": {
"collapsed": false
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"outputs": [],
"source": [
"from nose.tools import assert_equal\n",
"\n",
"class TestBinaryTree(object):\n",
"\n",
"\tdef test_insert_traversals (self):\n",
"\t\tmyTree = BinaryTree()\n",
"\t\tmyTree2 = BinaryTree()\n",
"\t\tfor num in [50, 30, 70, 10, 40, 60, 80, 7, 25, 38]:\n",
"\t\t\tmyTree.insert(num)\n",
"\t\t[myTree2.insert(num) for num in range (1, 100, 10)]\n",
"\n",
"\t\tprint(\"Test: insert checking with in order traversal\")\n",
"\t\texpectVal = [7, 10, 25, 30, 38, 40, 50, 60, 70, 80]\n",
"\t\tassert_equal(myTree.printInOrder(), expectVal)\n",
"\t\texpectVal = [1, 11, 21, 31, 41, 51, 61, 71, 81, 91]\n",
"\t\tassert_equal(myTree2.printInOrder(), expectVal)\n",
"\n",
"\t\tprint(\"Test: insert checking with post order traversal\")\n",
"\t\texpectVal = [7, 25, 10, 38, 40, 30, 60, 80, 70, 50]\n",
"\t\tassert_equal(myTree.printPostOrder(), expectVal)\n",
"\t\texpectVal = [91, 81, 71, 61, 51, 41, 31, 21, 11, 1]\n",
"\t\tassert_equal(myTree2.printPostOrder(), expectVal)\n",
"\n",
"\n",
"\t\tprint(\"Test: insert checking with pre order traversal\")\n",
"\t\texpectVal = [50, 30, 10, 7, 25, 40, 38, 70, 60, 80]\n",
"\t\tassert_equal(myTree.printPreOrder(), expectVal)\n",
"\t\texpectVal = [1, 11, 21, 31, 41, 51, 61, 71, 81, 91]\n",
"\t\tassert_equal(myTree2.printPreOrder(), expectVal)\n",
"\n",
"\n",
"\t\tprint(\"Success: test_insert_traversals\")\n",
"\n",
"\tdef test_max_min_nodes (self):\n",
"\t\tmyTree = BinaryTree()\n",
"\t\tmyTree.insert(5)\n",
"\t\tmyTree.insert(1)\n",
"\t\tmyTree.insert(21)\n",
"\n",
"\t\tprint(\"Test: max node\")\n",
"\t\tassert_equal(myTree.maxNode(), 21)\n",
"\t\tmyTree.insert(32)\n",
"\t\tassert_equal(myTree.maxNode(), 32)\n",
"\n",
"\t\tprint(\"Test: min node\")\n",
"\t\tassert_equal(myTree.minNode(), 1)\n",
"\n",
"\t\tprint(\"Test: min node inserting negative number\")\n",
"\t\tmyTree.insert(-10)\n",
"\t\tassert_equal(myTree.minNode(), -10)\n",
"\n",
"\t\tprint(\"Success: test_max_min_nodes\")\n",
"\n",
"\tdef test_delete (self):\n",
"\t\tmyTree = BinaryTree()\n",
"\t\tmyTree.insert(5)\n",
"\n",
"\t\tprint(\"Test: delete\")\n",
"\t\tmyTree.delete(5)\n",
"\t\tassert_equal(myTree.treeIsEmpty(), True)\n",
"\t\t\n",
"\t\tprint(\"Test: more complex deletions\")\n",
"\t\t[myTree.insert(x) for x in range(1, 5)]\n",
"\t\tmyTree.delete(2)\n",
"\t\tassert_equal(myTree.root.rightChild.data, 3)\n",
" \n",
"\t\tprint(\"Test: delete invalid value\")\n",
"\t\tassert_equal(myTree.delete(100), False)\n",
"\n",
"\n",
"\t\tprint(\"Success: test_delete\")\n",
"\n",
"def main():\n",
" testing = TestBinaryTree()\n",
" testing.test_insert_traversals()\n",
" testing.test_max_min_nodes()\n",
" testing.test_delete()\n",
" \n",
"if __name__=='__main__':\n",
" main()"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"**The following unit test is expected to fail until you solve the challenge.**"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Solution NoteBook\n",
"\n",
"Review the [Solution Notebook](http://nbviewer.ipython.org/github/donnemartin/interactive-coding-challenges/blob/master/graphs_trees/binary_tree_implementation/binary_tree_solution.ipynb) for a discussion on algorithms and code solutions."
]
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