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https://github.com/donnemartin/interactive-coding-challenges.git
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Add ransom note challenge
This commit is contained in:
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online_judges/ransom_note/__init__.py
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0
online_judges/ransom_note/__init__.py
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171
online_judges/ransom_note/ransom_note_challenge.ipynb
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171
online_judges/ransom_note/ransom_note_challenge.ipynb
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{
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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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"This notebook was prepared by [Donne Martin](https://github.com/donnemartin). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges)."
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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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"# Challenge Notebook"
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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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"## Problem: Given a magazine, see if a ransom note could have been written using the letters in the magazine.\n",
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"\n",
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"* [Constraints](#Constraints)\n",
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"* [Test Cases](#Test-Cases)\n",
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"* [Algorithm](#Algorithm)\n",
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"* [Code](#Code)\n",
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"* [Unit Test](#Unit-Test)\n",
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"* [Solution Notebook](#Solution-Notebook)"
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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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"## Constraints\n",
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"\n",
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"* Is this case sensitive?\n",
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" * Yes\n",
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"* Can we assume we're working with ASCII characters?\n",
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" * Yes\n",
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"* Can we scan the entire magazine, or should we scan only when necessary?\n",
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" * You can scan the entire magazine\n",
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"* Can we assume the inputs are valid?\n",
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" * No\n",
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"* Can we assume this fits memory?\n",
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" * Yes"
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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 Cases\n",
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"\n",
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"* None -> Exception\n",
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"* '', '' -> Exception\n",
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"* 'a', 'b' -> False\n",
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"* 'aa', 'ab' -> False\n",
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"* 'aa', 'aab' -> True"
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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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"## Algorithm\n",
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"\n",
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"Refer to the [Solution Notebook](). 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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]
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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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"## Code"
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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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"collapsed": false
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},
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"outputs": [],
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"source": [
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"class Solution(object):\n",
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"\n",
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" def match_note_to_magazine(self, ransom_note, magazine):\n",
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" # TODO: Implement me\n",
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" pass"
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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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"## Unit Test"
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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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"**The following unit test is expected to fail until you solve the challenge.**"
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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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"collapsed": false
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},
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"outputs": [],
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"source": [
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"# %load test_ransom_note.py\n",
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"from nose.tools import assert_equal, assert_raises\n",
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"\n",
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"\n",
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"class TestRansomNote(object):\n",
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"\n",
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" def test_ransom_note(self):\n",
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" solution = Solution()\n",
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" assert_raises(TypeError, solution.match_note_to_magazine, None, None)\n",
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" assert_equal(solution.match_note_to_magazine('', ''), True)\n",
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" assert_equal(solution.match_note_to_magazine('a', 'b'), False)\n",
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" assert_equal(solution.match_note_to_magazine('aa', 'ab'), False)\n",
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" assert_equal(solution.match_note_to_magazine('aa', 'aab'), True)\n",
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" print('Success: test_ransom_note')\n",
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"\n",
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"\n",
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"def main():\n",
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" test = TestRansomNote()\n",
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" test.test_ransom_note()\n",
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"\n",
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"\n",
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"if __name__ == '__main__':\n",
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" main()"
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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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"## Solution Notebook\n",
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"\n",
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"Review the [Solution Notebook]() for a discussion on algorithms and code solutions."
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]
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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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"version": 3
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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": "3.5.0"
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}
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},
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"nbformat": 4,
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"nbformat_minor": 0
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}
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201
online_judges/ransom_note/ransom_note_solution.ipynb
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online_judges/ransom_note/ransom_note_solution.ipynb
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@ -0,0 +1,201 @@
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{
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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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"This notebook was prepared by [Donne Martin](https://github.com/donnemartin). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges)."
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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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"# Solution Notebook"
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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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"## Problem: Given a magazine, see if a ransom note could have been written using the letters in the magazine.\n",
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"\n",
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"* [Constraints](#Constraints)\n",
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"* [Test Cases](#Test-Cases)\n",
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"* [Algorithm](#Algorithm)\n",
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"* [Code](#Code)\n",
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"* [Unit Test](#Unit-Test)"
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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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"## Constraints\n",
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"\n",
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"* Is this case sensitive?\n",
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" * Yes\n",
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"* Can we assume we're working with ASCII characters?\n",
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" * Yes\n",
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"* Can we scan the entire magazine, or should we scan only when necessary?\n",
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" * You can scan the entire magazine\n",
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"* Can we assume the inputs are valid?\n",
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" * No\n",
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"* Can we assume this fits memory?\n",
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" * Yes"
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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 Cases\n",
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"\n",
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"* None -> Exception\n",
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"* '', '' -> Exception\n",
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"* 'a', 'b' -> False\n",
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"* 'aa', 'ab' -> False\n",
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"* 'aa', 'aab' -> True"
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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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"## Algorithm\n",
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"\n",
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"* Build a dictionary of the magazine characters and counts.\n",
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"* Loop through each letter in the ransom note and see if there are enough letters in the magazine's dictionary.\n",
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"* Note: You could make this more efficient by not scanning the entire magazine all at once, but instead scan just in time as you run out of letters in the dictionary.\n",
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"\n",
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"Complexity:\n",
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"* Time: O(n+m), where n is the length of the ransom note and m is the length of the magazine\n",
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"* Space: O(n+m)"
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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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"## Code"
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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": 1,
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"metadata": {
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"collapsed": false
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},
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"outputs": [],
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"source": [
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"class Solution(object):\n",
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"\n",
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" def match_note_to_magazine(self, ransom_note, magazine):\n",
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" if ransom_note is None or magazine is None:\n",
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" raise TypeError('ransom_note or magazine cannot be None')\n",
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" seen_chars = {}\n",
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" for char in magazine:\n",
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" if char in seen_chars:\n",
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" seen_chars[char] += 1\n",
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" else:\n",
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" seen_chars[char] = 1\n",
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" for char in ransom_note:\n",
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" try:\n",
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" seen_chars[char] -= 1\n",
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" except KeyError:\n",
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" return False\n",
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" if seen_chars[char] < 0:\n",
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" return False\n",
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" return True"
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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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"## Unit Test"
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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": 2,
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"metadata": {
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"collapsed": false
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},
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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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"Overwriting test_ransom_note.py\n"
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]
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}
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],
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"source": [
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"%%writefile test_ransom_note.py\n",
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"from nose.tools import assert_equal, assert_raises\n",
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"\n",
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"\n",
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"class TestRansomNote(object):\n",
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"\n",
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" def test_ransom_note(self):\n",
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" solution = Solution()\n",
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" assert_raises(TypeError, solution.match_note_to_magazine, None, None)\n",
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" assert_equal(solution.match_note_to_magazine('', ''), True)\n",
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" assert_equal(solution.match_note_to_magazine('a', 'b'), False)\n",
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" assert_equal(solution.match_note_to_magazine('aa', 'ab'), False)\n",
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" assert_equal(solution.match_note_to_magazine('aa', 'aab'), True)\n",
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" print('Success: test_ransom_note')\n",
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"\n",
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"\n",
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"def main():\n",
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" test = TestRansomNote()\n",
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" test.test_ransom_note()\n",
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"\n",
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"\n",
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"if __name__ == '__main__':\n",
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" main()"
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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": 3,
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"metadata": {
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"collapsed": false
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},
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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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"Success: test_ransom_note\n"
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]
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}
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],
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"source": [
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"%run -i test_ransom_note.py"
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]
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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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"version": 3
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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": "3.5.0"
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}
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},
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"nbformat": 4,
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"nbformat_minor": 0
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}
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22
online_judges/ransom_note/test_ransom_note.py
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online_judges/ransom_note/test_ransom_note.py
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from nose.tools import assert_equal, assert_raises
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class TestRansomNote(object):
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def test_ransom_note(self):
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solution = Solution()
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assert_raises(TypeError, solution.match_note_to_magazine, None, None)
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assert_equal(solution.match_note_to_magazine('', ''), True)
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assert_equal(solution.match_note_to_magazine('a', 'b'), False)
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assert_equal(solution.match_note_to_magazine('aa', 'ab'), False)
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assert_equal(solution.match_note_to_magazine('aa', 'aab'), True)
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print('Success: test_ransom_note')
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def main():
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test = TestRansomNote()
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test.test_ransom_note()
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if __name__ == '__main__':
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main()
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