diff --git a/online_judges/nim/__init__.py b/online_judges/nim/__init__.py new file mode 100644 index 0000000..e69de29 diff --git a/online_judges/nim/nim_challenge.ipynb b/online_judges/nim/nim_challenge.ipynb new file mode 100644 index 0000000..068e7bc --- /dev/null +++ b/online_judges/nim/nim_challenge.ipynb @@ -0,0 +1,179 @@ +{ + "cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "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)." + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Challenge Notebook" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Problem: Determine whether you can win the Nim game given the remaining stones.\n", + "\n", + "See the [LeetCode](https://leetcode.com/problems/nim-game/) problem page.\n", + "\n", + "You are playing the following Nim Game with your friend: There is a heap of stones on the table, each time one of you take turns to remove 1 to 3 stones. The one who removes the last stone will be the winner. You will take the first turn to remove the stones.\n", + "\n", + "Both of you are very clever and have optimal strategies for the game. Write a function to determine whether you can win the game given the number of stones in the heap.\n", + "\n", + "For example, if there are 4 stones in the heap, then you will never win the game: no matter 1, 2, or 3 stones you remove, the last stone will always be removed by your friend.\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", + "* Is the input an int?\n", + " * Yes\n", + "* Is the output a boolean?\n", + " * Yes\n", + "* Can we assume the inputs are valid?\n", + " * No\n", + "* Can we assume this fits memory?\n", + " * Yes" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Test Cases\n", + "\n", + "* None -> TypeError\n", + "* 1, 2, or 3 -> True\n", + "* 4 -> False\n", + "* 7 -> True\n", + "* 40 -> False" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Algorithm\n", + "\n", + "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." + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Code" + ] + }, + { + "cell_type": "code", + "execution_count": null, + "metadata": { + "collapsed": false + }, + "outputs": [], + "source": [ + "class Solution(object):\n", + "\n", + " def can_win_nim(self, num_stones_left):\n", + " # TODO: Implement me\n", + " pass" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Unit Test" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "**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_can_win_nim.py\n", + "from nose.tools import assert_equal, assert_raises\n", + "\n", + "\n", + "class TestSolution(object):\n", + "\n", + " def test_can_win_nim(self):\n", + " solution = Solution()\n", + " assert_raises(TypeError, solution.can_win_nim, None)\n", + " assert_equal(solution.can_win_nim(1), True)\n", + " assert_equal(solution.can_win_nim(2), True)\n", + " assert_equal(solution.can_win_nim(3), True)\n", + " assert_equal(solution.can_win_nim(4), False)\n", + " assert_equal(solution.can_win_nim(7), True)\n", + " assert_equal(solution.can_win_nim(40), False)\n", + " print('Success: test_can_win_nim')\n", + "\n", + "\n", + "def main():\n", + " test = TestSolution()\n", + " test.test_can_win_nim()\n", + "\n", + "\n", + "if __name__ == '__main__':\n", + " main()" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Solution Notebook\n", + "\n", + "Review the [Solution Notebook]() for a discussion on algorithms and code solutions." + ] + } + ], + "metadata": { + "kernelspec": { + "display_name": "Python 3", + "language": "python", + "name": "python3" + }, + "language_info": { + "codemirror_mode": { + "name": "ipython", + "version": 3 + }, + "file_extension": ".py", + "mimetype": "text/x-python", + "name": "python", + "nbconvert_exporter": "python", + "pygments_lexer": "ipython3", + "version": "3.5.0" + } + }, + "nbformat": 4, + "nbformat_minor": 0 +} diff --git a/online_judges/nim/nim_solution.ipynb b/online_judges/nim/nim_solution.ipynb new file mode 100644 index 0000000..0db4ec5 --- /dev/null +++ b/online_judges/nim/nim_solution.ipynb @@ -0,0 +1,192 @@ +{ + "cells": [ + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "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)." + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "# Solution Notebook" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Problem: Determine whether you can win the Nim game given the remaining stones.\n", + "\n", + "See the [LeetCode](https://leetcode.com/problems/nim-game/) problem page.\n", + "\n", + "You are playing the following Nim Game with your friend: There is a heap of stones on the table, each time one of you take turns to remove 1 to 3 stones. The one who removes the last stone will be the winner. You will take the first turn to remove the stones.\n", + "\n", + "Both of you are very clever and have optimal strategies for the game. Write a function to determine whether you can win the game given the number of stones in the heap.\n", + "\n", + "For example, if there are 4 stones in the heap, then you will never win the game: no matter 1, 2, or 3 stones you remove, the last stone will always be removed by your friend.\n", + "\n", + "* [Constraints](#Constraints)\n", + "* [Test Cases](#Test-Cases)\n", + "* [Algorithm](#Algorithm)\n", + "* [Code](#Code)\n", + "* [Unit Test](#Unit-Test)" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Constraints\n", + "\n", + "* Is the input an int?\n", + " * Yes\n", + "* Is the output a boolean?\n", + " * Yes\n", + "* Can we assume the inputs are valid?\n", + " * Yes\n", + "* Can we assume this fits memory?\n", + " * Yes" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Test Cases\n", + "\n", + "* None -> TypeError\n", + "* 1, 2, or 3 -> True\n", + "* 4 -> False\n", + "* 7 -> True\n", + "* 40 -> False" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Algorithm\n", + "\n", + "This is somewhat of a one-trick puzzle, where the only way you can lose if you take the first stone while playing optimally is if the number of remaining stones is divisible by 4.\n", + "\n", + "Complexity:\n", + "* Time: O(1)\n", + "* Space: O(1)" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Code" + ] + }, + { + "cell_type": "code", + "execution_count": 1, + "metadata": { + "collapsed": false + }, + "outputs": [], + "source": [ + "class Solution(object):\n", + "\n", + " def can_win_nim(self, num_stones_left):\n", + " return num_stones_left % 4 != 0" + ] + }, + { + "cell_type": "markdown", + "metadata": {}, + "source": [ + "## Unit Test" + ] + }, + { + "cell_type": "code", + "execution_count": 2, + "metadata": { + "collapsed": false + }, + "outputs": [ + { + "name": "stdout", + "output_type": "stream", + "text": [ + "Overwriting test_can_win_nim.py\n" + ] + } + ], + "source": [ + "%%writefile test_can_win_nim.py\n", + "from nose.tools import assert_equal, assert_raises\n", + "\n", + "\n", + "class TestSolution(object):\n", + "\n", + " def test_can_win_nim(self):\n", + " solution = Solution()\n", + " assert_raises(TypeError, solution.can_win_nim, None)\n", + " assert_equal(solution.can_win_nim(1), True)\n", + " assert_equal(solution.can_win_nim(2), True)\n", + " assert_equal(solution.can_win_nim(3), True)\n", + " assert_equal(solution.can_win_nim(4), False)\n", + " assert_equal(solution.can_win_nim(7), True)\n", + " assert_equal(solution.can_win_nim(40), False)\n", + " print('Success: test_can_win_nim')\n", + "\n", + "\n", + "def main():\n", + " test = TestSolution()\n", + " test.test_can_win_nim()\n", + "\n", + "\n", + "if __name__ == '__main__':\n", + " main()" + ] + }, + { + "cell_type": "code", + "execution_count": 3, + "metadata": { + "collapsed": false + }, + "outputs": [ + { + "name": "stdout", + "output_type": "stream", + "text": [ + "Success: test_can_win_nim\n" + ] + } + ], + "source": [ + "%run -i test_can_win_nim.py" + ] + } + ], + "metadata": { + "kernelspec": { + "display_name": "Python 3", + "language": "python", + "name": "python3" + }, + "language_info": { + "codemirror_mode": { + "name": "ipython", + "version": 3 + }, + "file_extension": ".py", + "mimetype": "text/x-python", + "name": "python", + "nbconvert_exporter": "python", + "pygments_lexer": "ipython3", + "version": "3.5.0" + } + }, + "nbformat": 4, + "nbformat_minor": 0 +} diff --git a/online_judges/nim/test_can_win_nim.py b/online_judges/nim/test_can_win_nim.py new file mode 100644 index 0000000..92de456 --- /dev/null +++ b/online_judges/nim/test_can_win_nim.py @@ -0,0 +1,24 @@ +from nose.tools import assert_equal, assert_raises + + +class TestSolution(object): + + def test_can_win_nim(self): + solution = Solution() + assert_raises(TypeError, solution.can_win_nim, None) + assert_equal(solution.can_win_nim(1), True) + assert_equal(solution.can_win_nim(2), True) + assert_equal(solution.can_win_nim(3), True) + assert_equal(solution.can_win_nim(4), False) + assert_equal(solution.can_win_nim(7), True) + assert_equal(solution.can_win_nim(40), False) + print('Success: test_can_win_nim') + + +def main(): + test = TestSolution() + test.test_can_win_nim() + + +if __name__ == '__main__': + main() \ No newline at end of file