diff --git a/arrays_strings/hash_map/hash_map_challenge.ipynb b/arrays_strings/hash_map/hash_map_challenge.ipynb
new file mode 100644
index 0000000..a8801d1
--- /dev/null
+++ b/arrays_strings/hash_map/hash_map_challenge.ipynb
@@ -0,0 +1,217 @@
+{
+ "cells": [
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://github.com/donnemartin/coding-challenges)."
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "# Challenge Notebook"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Problem: Implement a hash table with set, get, and remove methods.\n",
+ "\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",
+ "\n",
+ "*Problem statements are sometimes ambiguous. Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n",
+ "\n",
+ "* For simplicity, are the keys integers only?\n",
+ " * Yes\n",
+ "* For collision resolution, can we use linked lists?\n",
+ " * Yes\n",
+ "* Do we have to worry about load factors?\n",
+ " * No"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Test Cases\n",
+ "\n",
+ "* get on an empty hash table index\n",
+ "* set on an empty hash table index\n",
+ "* set on a non empty hash table index\n",
+ "* set on a key that already exists\n",
+ "* remove on a key with an entry\n",
+ "* remove on a key without an entry"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Algorithm\n",
+ "\n",
+ "Refer to the [Solution Notebook](http://nbviewer.ipython.org/github/donnemartin/coding-challenges/blob/master/arrays_strings/hash_map/hash_map_solution.ipynb). If you are stuck and need a hint, the solution notebook's algorithm discussion might be a good place to start."
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Code"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": null,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [],
+ "source": [
+ "class Item(object):\n",
+ " \n",
+ " def __init__(self, key, value):\n",
+ " # TODO: Implement me\n",
+ " pass\n",
+ "\n",
+ "class HashTable(object):\n",
+ " \n",
+ " def __init__(self, size):\n",
+ " # TODO: Implement me\n",
+ " pass\n",
+ "\n",
+ " def hash_function(self, key):\n",
+ " # TODO: Implement me\n",
+ " pass\n",
+ "\n",
+ " def set(self, key, value):\n",
+ " # TODO: Implement me\n",
+ " pass\n",
+ "\n",
+ " def get(self, key):\n",
+ " # TODO: Implement me\n",
+ " pass\n",
+ "\n",
+ " def remove(self, key):\n",
+ " # TODO: Implement me\n",
+ " pass"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Unit Test"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "\n",
+ "\n",
+ "**The following unit test is expected to fail until you solve the challenge.**"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": null,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [],
+ "source": [
+ "# %load test_hash_map.py\n",
+ "from nose.tools import assert_equal\n",
+ "\n",
+ "\n",
+ "class TestHashMap(object):\n",
+ " \n",
+ " # TODO: It would be better if we had unit tests for each\n",
+ " # method in addition to the following end-to-end test\n",
+ " def test_end_to_end(self):\n",
+ " hash_table = HashTable(10)\n",
+ " \n",
+ " print(\"Test: get on an empty hash table index\")\n",
+ " assert_equal(hash_table.get(0), None)\n",
+ " \n",
+ " print(\"Test: set on an empty hash table index\")\n",
+ " hash_table.set(0, 'foo')\n",
+ " assert_equal(hash_table.get(0), 'foo')\n",
+ " hash_table.set(1, 'bar')\n",
+ " assert_equal(hash_table.get(1), 'bar')\n",
+ " \n",
+ " print(\"Test: set on a non empty hash table index\")\n",
+ " hash_table.set(10, 'foo2')\n",
+ " assert_equal(hash_table.get(0), 'foo')\n",
+ " assert_equal(hash_table.get(10), 'foo2')\n",
+ " \n",
+ " print(\"Test: set on a key that already exists\")\n",
+ " hash_table.set(10, 'foo3')\n",
+ " assert_equal(hash_table.get(0), 'foo')\n",
+ " assert_equal(hash_table.get(10), 'foo3')\n",
+ " \n",
+ " print(\"Test: remove on a key that already exists\")\n",
+ " hash_table.remove(10)\n",
+ " assert_equal(hash_table.get(0), 'foo')\n",
+ " assert_equal(hash_table.get(10), None)\n",
+ " \n",
+ " print(\"Test: remove on a key that doesn't exist\")\n",
+ " hash_table.remove(-1)\n",
+ " \n",
+ " print('Success: test_end_to_end')\n",
+ "\n",
+ "def main():\n",
+ " test = TestHashMap()\n",
+ " test.test_end_to_end()\n",
+ " \n",
+ "if __name__ == '__main__':\n",
+ " main()"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Solution Notebook\n",
+ "\n",
+ "Review the [Solution Notebook](http://nbviewer.ipython.org/github/donnemartin/coding-challenges/blob/master/arrays_strings/hash_map/hash_map_solution.ipynb) for a discussion on algorithms and code solutions."
+ ]
+ }
+ ],
+ "metadata": {
+ "kernelspec": {
+ "display_name": "Python 2",
+ "language": "python",
+ "name": "python2"
+ },
+ "language_info": {
+ "codemirror_mode": {
+ "name": "ipython",
+ "version": 2
+ },
+ "file_extension": ".py",
+ "mimetype": "text/x-python",
+ "name": "python",
+ "nbconvert_exporter": "python",
+ "pygments_lexer": "ipython2",
+ "version": "2.7.10"
+ }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/arrays_strings/hash_map/hash_map_solution.ipynb b/arrays_strings/hash_map/hash_map_solution.ipynb
index 68b6b39..908957e 100644
--- a/arrays_strings/hash_map/hash_map_solution.ipynb
+++ b/arrays_strings/hash_map/hash_map_solution.ipynb
@@ -4,7 +4,14 @@
"cell_type": "markdown",
"metadata": {},
"source": [
- "This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://bit.ly/code-notes)."
+ "This notebook was prepared by [Donne Martin](http://donnemartin.com). Source and license info is on [GitHub](https://github.com/donnemartin/coding-challenges)."
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "# Solution Notebook"
]
},
{
@@ -17,7 +24,6 @@
"* [Test Cases](#Test-Cases)\n",
"* [Algorithm](#Algorithm)\n",
"* [Code](#Code)\n",
- "* [Pythonic-Code](#Pythonic-Code)\n",
"* [Unit Test](#Unit-Test)"
]
},
@@ -27,7 +33,7 @@
"source": [
"## Constraints\n",
"\n",
- "*Problem statements are often intentionally ambiguous. Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n",
+ "*Problem statements are sometimes ambiguous. Identifying constraints and stating assumptions can help to ensure you code the intended solution.*\n",
"\n",
"* For simplicity, are the keys integers only?\n",
" * Yes\n",
@@ -111,11 +117,13 @@
"outputs": [],
"source": [
"class Item(object):\n",
+ " \n",
" def __init__(self, key, value):\n",
" self.key = key\n",
" self.value = value\n",
"\n",
"class HashTable(object):\n",
+ " \n",
" def __init__(self, size):\n",
" self.size = size\n",
" self.table = [[] for _ in xrange(self.size)]\n",
@@ -152,13 +160,6 @@
"## Unit Test"
]
},
- {
- "cell_type": "markdown",
- "metadata": {},
- "source": [
- "*It is important to identify and run through general and edge cases from the [Test Cases](#Test-Cases) section by hand. You generally will not be asked to write a unit test like what is shown below.*"
- ]
- },
{
"cell_type": "code",
"execution_count": 2,
@@ -170,20 +171,17 @@
"name": "stdout",
"output_type": "stream",
"text": [
- "Test: get on an empty hash table index\n",
- "Test: set on an empty hash table index\n",
- "Test: set on a non empty hash table index\n",
- "Test: set on a key that already exists\n",
- "Test: remove on a key that already exists\n",
- "Test: remove on a key that doesn't exist\n",
- "Success: test_end_to_end\n"
+ "Overwriting test_hash_map.py\n"
]
}
],
"source": [
+ "%%writefile test_hash_map.py\n",
"from nose.tools import assert_equal\n",
"\n",
- "class Test(object):\n",
+ "\n",
+ "class TestHashMap(object):\n",
+ " \n",
" # TODO: It would be better if we had unit tests for each\n",
" # method in addition to the following end-to-end test\n",
" def test_end_to_end(self):\n",
@@ -218,9 +216,37 @@
" \n",
" print('Success: test_end_to_end')\n",
"\n",
+ "def main():\n",
+ " test = TestHashMap()\n",
+ " test.test_end_to_end()\n",
+ " \n",
"if __name__ == '__main__':\n",
- " test = Test()\n",
- " test.test_end_to_end()"
+ " main()"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 3,
+ "metadata": {
+ "collapsed": false
+ },
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "Test: get on an empty hash table index\n",
+ "Test: set on an empty hash table index\n",
+ "Test: set on a non empty hash table index\n",
+ "Test: set on a key that already exists\n",
+ "Test: remove on a key that already exists\n",
+ "Test: remove on a key that doesn't exist\n",
+ "Success: test_end_to_end\n"
+ ]
+ }
+ ],
+ "source": [
+ "run -i test_hash_map.py"
]
}
],
diff --git a/arrays_strings/hash_map/test_hash_map.py b/arrays_strings/hash_map/test_hash_map.py
new file mode 100644
index 0000000..2ed8a77
--- /dev/null
+++ b/arrays_strings/hash_map/test_hash_map.py
@@ -0,0 +1,45 @@
+from nose.tools import assert_equal
+
+
+class TestHashMap(object):
+
+ # TODO: It would be better if we had unit tests for each
+ # method in addition to the following end-to-end test
+ def test_end_to_end(self):
+ hash_table = HashTable(10)
+
+ print("Test: get on an empty hash table index")
+ assert_equal(hash_table.get(0), None)
+
+ print("Test: set on an empty hash table index")
+ hash_table.set(0, 'foo')
+ assert_equal(hash_table.get(0), 'foo')
+ hash_table.set(1, 'bar')
+ assert_equal(hash_table.get(1), 'bar')
+
+ print("Test: set on a non empty hash table index")
+ hash_table.set(10, 'foo2')
+ assert_equal(hash_table.get(0), 'foo')
+ assert_equal(hash_table.get(10), 'foo2')
+
+ print("Test: set on a key that already exists")
+ hash_table.set(10, 'foo3')
+ assert_equal(hash_table.get(0), 'foo')
+ assert_equal(hash_table.get(10), 'foo3')
+
+ print("Test: remove on a key that already exists")
+ hash_table.remove(10)
+ assert_equal(hash_table.get(0), 'foo')
+ assert_equal(hash_table.get(10), None)
+
+ print("Test: remove on a key that doesn't exist")
+ hash_table.remove(-1)
+
+ print('Success: test_end_to_end')
+
+def main():
+ test = TestHashMap()
+ test.test_end_to_end()
+
+if __name__ == '__main__':
+ main()
\ No newline at end of file