diff --git a/arrays_strings/compress/compress_challenge.ipynb b/arrays_strings/compress/compress_challenge.ipynb
new file mode 100644
index 0000000..d256e96
--- /dev/null
+++ b/arrays_strings/compress/compress_challenge.ipynb
@@ -0,0 +1,173 @@
+{
+ "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: Compress a string such that 'AAABCCDDDD' becomes 'A3B1C2D4'\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",
+ "* Can we assume the string is ASCII?\n",
+ " * Yes\n",
+ " * Note: Unicode strings could require special handling depending on your language\n",
+ "* Can you use additional data structures? \n",
+ " * Yes\n",
+ "* Is this case sensitive?\n",
+ " * Yes\n",
+ "* Do you compress even if it doesn't save space?\n",
+ " * No"
+ ]
+ },
+ {
+ "cell_type": "markdown",
+ "metadata": {},
+ "source": [
+ "## Test Cases\n",
+ "\n",
+ "* None -> None\n",
+ "* '' -> ''\n",
+ "* 'AABBCC' -> 'AABBCC'\n",
+ "* 'AAABCCDDDD' -> 'A3B1C2D4'"
+ ]
+ },
+ {
+ "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/compress/compress_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": [
+ "def compress_string(string):\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_compress.py\n",
+ "from nose.tools import assert_equal\n",
+ "\n",
+ "\n",
+ "class TestCompress(object):\n",
+ " \n",
+ " def test_compress(self, func):\n",
+ " assert_equal(func(None), None)\n",
+ " assert_equal(func(''), '')\n",
+ " assert_equal(func('AABBCC'), 'AABBCC')\n",
+ " assert_equal(func('AAABCCDDDD'), 'A3B1C2D4')\n",
+ " print('Success: test_compress')\n",
+ "\n",
+ "def main():\n",
+ " test = TestCompress()\n",
+ " test.test_compress(compress_string)\n",
+ " try:\n",
+ " test.test_compress(compress_string_alt)\n",
+ " except NameError:\n",
+ " # Alternate solutions are only defined\n",
+ " # in the solutions file\n",
+ " pass\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/compress/compress_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/compress/compress_solution.ipynb b/arrays_strings/compress/compress_solution.ipynb
index 4da5513..0f8fc80 100644
--- a/arrays_strings/compress/compress_solution.ipynb
+++ b/arrays_strings/compress/compress_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"
]
},
{
@@ -28,9 +35,9 @@
"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",
- "* Can I assume the string is ASCII?\n",
+ "* Can we assume the string is ASCII?\n",
" * Yes\n",
" * Note: Unicode strings could require special handling depending on your language\n",
"* Can you use additional data structures? \n",
@@ -47,9 +54,9 @@
"source": [
"## Test Cases\n",
"\n",
- "* NULL\n",
+ "* None -> None\n",
"* '' -> ''\n",
- "* 'ABC' -> 'ABC'\n",
+ "* 'AABBCC' -> 'AABBCC'\n",
"* 'AAABCCDDDD' -> 'A3B1C2D4'"
]
},
@@ -59,9 +66,7 @@
"source": [
"## Algorithm: List\n",
"\n",
- "Since Python strings are immutable, we'll use a list of characters instead to exercise in-place string manipulation as you would get with a C string (which is null terminated, as seen in the diagram below). Python does not use a null-terminator.\n",
- "\n",
- "\n",
+ "Since Python strings are immutable, we'll use a list of characters instead to exercise string manipulation as you would get with a C string. We'll convert the list to a string at the end of the algorithm.\n",
"\n",
"* Calculate the size of the compressed string\n",
"* If the compressed string size is >= string size, return string\n",
@@ -79,7 +84,7 @@
"\n",
"Complexity:\n",
"* Time: O(n)\n",
- "* Space: O(2m) where m is the size of the compressed list and the resulting string copied from the list"
+ "* Space: O(n) additional space for the list"
]
},
{
@@ -138,20 +143,15 @@
"source": [
"## Algorithm: Byte Array\n",
"\n",
- "The byte array algorithm similar when using a list, except we will need to work with the bytearray's character codes instead of the characters as we did above when we implemented this solution with a list.\n",
+ "As a bonus solution, we can solve this problem with a byte array.\n",
+ "\n",
+ "The byte array algorithm similar when using a list, except we will need to work with the bytearray's character codes (using the function ord) instead of the characters as we did above when we implemented this solution with a list.\n",
"\n",
"Complexity:\n",
"* Time: O(n)\n",
"* Space: O(m) where m is the size of the compressed bytearray"
]
},
- {
- "cell_type": "markdown",
- "metadata": {},
- "source": [
- "## Code: Byte Array"
- ]
- },
{
"cell_type": "code",
"execution_count": 2,
@@ -201,14 +201,14 @@
"cell_type": "markdown",
"metadata": {},
"source": [
- "## Unit Test"
+ "## Code: Byte Array"
]
},
{
"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.*"
+ "## Unit Test"
]
},
{
@@ -217,6 +217,49 @@
"metadata": {
"collapsed": false
},
+ "outputs": [
+ {
+ "name": "stdout",
+ "output_type": "stream",
+ "text": [
+ "Overwriting test_compress.py\n"
+ ]
+ }
+ ],
+ "source": [
+ "%%writefile test_compress.py\n",
+ "from nose.tools import assert_equal\n",
+ "\n",
+ "\n",
+ "class TestCompress(object):\n",
+ " \n",
+ " def test_compress(self, func):\n",
+ " assert_equal(func(None), None)\n",
+ " assert_equal(func(''), '')\n",
+ " assert_equal(func('AABBCC'), 'AABBCC')\n",
+ " assert_equal(func('AAABCCDDDD'), 'A3B1C2D4')\n",
+ " print('Success: test_compress')\n",
+ "\n",
+ "def main():\n",
+ " test = TestCompress()\n",
+ " test.test_compress(compress_string)\n",
+ " try:\n",
+ " test.test_compress(compress_string_alt)\n",
+ " except NameError:\n",
+ " # Alternate solutions are only defined\n",
+ " # in the solutions file\n",
+ " pass\n",
+ "\n",
+ "if __name__ == '__main__':\n",
+ " main()"
+ ]
+ },
+ {
+ "cell_type": "code",
+ "execution_count": 4,
+ "metadata": {
+ "collapsed": false
+ },
"outputs": [
{
"name": "stdout",
@@ -228,20 +271,7 @@
}
],
"source": [
- "from nose.tools import assert_equal\n",
- "\n",
- "class Test(object):\n",
- " def test_compress(self, func):\n",
- " assert_equal(func(None), None)\n",
- " assert_equal(func(''), '')\n",
- " assert_equal(func('ABC'), 'ABC')\n",
- " assert_equal(func('AAABCCDDDD'), 'A3B1C2D4')\n",
- " print('Success: test_compress')\n",
- "\n",
- "if __name__ == '__main__':\n",
- " test = Test()\n",
- " test.test_compress(compress_string)\n",
- " test.test_compress(compress_string_alt)"
+ "%run -i test_compress.py"
]
}
],
diff --git a/arrays_strings/compress/test_compress.py b/arrays_strings/compress/test_compress.py
new file mode 100644
index 0000000..fef9e62
--- /dev/null
+++ b/arrays_strings/compress/test_compress.py
@@ -0,0 +1,24 @@
+from nose.tools import assert_equal
+
+
+class TestCompress(object):
+
+ def test_compress(self, func):
+ assert_equal(func(None), None)
+ assert_equal(func(''), '')
+ assert_equal(func('AABBCC'), 'AABBCC')
+ assert_equal(func('AAABCCDDDD'), 'A3B1C2D4')
+ print('Success: test_compress')
+
+def main():
+ test = TestCompress()
+ test.test_compress(compress_string)
+ try:
+ test.test_compress(compress_string_alt)
+ except NameError:
+ # Alternate solutions are only defined
+ # in the solutions file
+ pass
+
+if __name__ == '__main__':
+ main()
\ No newline at end of file