From 22971b5005d33f7b8f79f61089640e3e3b6575ee Mon Sep 17 00:00:00 2001
From: Donne Martin <donne.martin@gmail.com>
Date: Wed, 29 Mar 2017 04:31:39 -0400
Subject: [PATCH] Add move zeroes challenge

---
 online_judges/move_zeroes/__init__.py         |   0
 .../move_zeroes/move_zeroes_challenge.ipynb   | 189 +++++++++++++
 .../move_zeroes/move_zeroes_solution.ipynb    | 250 ++++++++++++++++++
 online_judges/move_zeroes/test_move_zeroes.py |  36 +++
 4 files changed, 475 insertions(+)
 create mode 100644 online_judges/move_zeroes/__init__.py
 create mode 100644 online_judges/move_zeroes/move_zeroes_challenge.ipynb
 create mode 100644 online_judges/move_zeroes/move_zeroes_solution.ipynb
 create mode 100644 online_judges/move_zeroes/test_move_zeroes.py

diff --git a/online_judges/move_zeroes/__init__.py b/online_judges/move_zeroes/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/online_judges/move_zeroes/move_zeroes_challenge.ipynb b/online_judges/move_zeroes/move_zeroes_challenge.ipynb
new file mode 100644
index 0000000..d9b223c
--- /dev/null
+++ b/online_judges/move_zeroes/move_zeroes_challenge.ipynb
@@ -0,0 +1,189 @@
+{
+ "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: Move all zeroes in a list to the end.\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 array of ints?\n",
+    "    * Yes\n",
+    "* Is the output a new array of ints?\n",
+    "    * No, do this in-place\n",
+    "* Do we need to maintain ordering of non-zero values?\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",
+    "<pre>\n",
+    "* None -> TypeError\n",
+    "* [0, 1, 0, 3, 12]\n",
+    "* [1, 0] -> [1, 0]\n",
+    "* [0, 1] -> [1, 0]\n",
+    "* [0] -> [0]\n",
+    "* [1] -> [1]\n",
+    "* [1, 1] -> [1, 1]\n",
+    "</pre>"
+   ]
+  },
+  {
+   "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 move_zeroes(self, nums):\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_move_zeroes.py\n",
+    "from nose.tools import assert_equal, assert_raises\n",
+    "\n",
+    "\n",
+    "class TestMoveZeroes(object):\n",
+    "\n",
+    "    def test_move_zeroes(self):\n",
+    "        solution = Solution()\n",
+    "        assert_raises(TypeError, solution.move_zeroes, None)\n",
+    "        array = [0, 1, 0, 3, 12]\n",
+    "        solution.move_zeroes(array)\n",
+    "        assert_equal(array, [1, 3, 12, 0, 0])\n",
+    "        array = [1, 0]\n",
+    "        solution.move_zeroes(array)\n",
+    "        assert_equal(array, [1, 0])\n",
+    "        array = [0, 1]\n",
+    "        solution.move_zeroes(array)\n",
+    "        assert_equal(array, [1, 0])\n",
+    "        array = [0]\n",
+    "        solution.move_zeroes(array)\n",
+    "        assert_equal(array, [0])\n",
+    "        array = [1]\n",
+    "        solution.move_zeroes(array)\n",
+    "        assert_equal(array, [1])\n",
+    "        array = [1, 1]\n",
+    "        solution.move_zeroes(array)\n",
+    "        assert_equal(array, [1, 1])\n",
+    "        print('Success: test_move_zeroes')\n",
+    "\n",
+    "\n",
+    "def main():\n",
+    "    test = TestMoveZeroes()\n",
+    "    test.test_move_zeroes()\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/move_zeroes/move_zeroes_solution.ipynb b/online_judges/move_zeroes/move_zeroes_solution.ipynb
new file mode 100644
index 0000000..7fabe45
--- /dev/null
+++ b/online_judges/move_zeroes/move_zeroes_solution.ipynb
@@ -0,0 +1,250 @@
+{
+ "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: Move all zeroes in a list to the end.\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 array of ints?\n",
+    "    * Yes\n",
+    "* Is the output a new array of ints?\n",
+    "    * No, do this in-place\n",
+    "* Do we need to maintain ordering of non-zero values?\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",
+    "<pre>\n",
+    "* None -> TypeError\n",
+    "* [0, 1, 0, 3, 12] -> [1, 3, 12, 0, 0]\n",
+    "* [1, 0] -> [1, 0]\n",
+    "* [0, 1] -> [1, 0]\n",
+    "* [0] -> [0]\n",
+    "* [1] -> [1]\n",
+    "* [1, 1] -> [1, 1]\n",
+    "</pre>"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Algorithm\n",
+    "\n",
+    "* pos = 0\n",
+    "* Loop through each item in the input\n",
+    "    * If the item != 0, set input[pos] = item\n",
+    "        * pos++\n",
+    "* Fill input[pos:] with zeroes\n",
+    "\n",
+    "<pre>\n",
+    " |\n",
+    "[0, 1, 0, 3, 12]\n",
+    " ^\n",
+    "    |\n",
+    "[0, 1, 0, 3, 12]\n",
+    " ^\n",
+    "    |\n",
+    "[1, 1, 0, 3, 12]\n",
+    " ^\n",
+    "       |\n",
+    "[1, 1, 0, 3, 12]\n",
+    "    ^\n",
+    "          |\n",
+    "[1, 1, 0, 3, 12]\n",
+    "    ^\n",
+    "          |\n",
+    "[1, 3, 0, 3, 12]\n",
+    "    ^\n",
+    "              |\n",
+    "[1, 3, 0, 3, 12]\n",
+    "       ^\n",
+    "              |\n",
+    "[1, 3, 12, 3, 12]\n",
+    "       ^\n",
+    "\n",
+    "Fill right with zeroes:\n",
+    "\n",
+    "[1, 3, 12, 3, 12]\n",
+    "           ^\n",
+    "[1, 3, 12, 0, 12]\n",
+    "           ^\n",
+    "[1, 3, 12, 0, 0]\n",
+    "              ^\n",
+    "</pre>\n",
+    "\n",
+    "Complexity:\n",
+    "* Time: O(n)\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 move_zeroes(self, nums):\n",
+    "        if nums is None:\n",
+    "            raise TypeError('nums cannot be None')\n",
+    "        pos = 0\n",
+    "        for num in nums:\n",
+    "            if num != 0:\n",
+    "                nums[pos] = num\n",
+    "                pos += 1\n",
+    "        if pos < len(nums):\n",
+    "            nums[pos:] = [0] * (len(nums) - pos)"
+   ]
+  },
+  {
+   "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_move_zeroes.py\n"
+     ]
+    }
+   ],
+   "source": [
+    "%%writefile test_move_zeroes.py\n",
+    "from nose.tools import assert_equal, assert_raises\n",
+    "\n",
+    "\n",
+    "class TestMoveZeroes(object):\n",
+    "\n",
+    "    def test_move_zeroes(self):\n",
+    "        solution = Solution()\n",
+    "        assert_raises(TypeError, solution.move_zeroes, None)\n",
+    "        array = [0, 1, 0, 3, 12]\n",
+    "        solution.move_zeroes(array)\n",
+    "        assert_equal(array, [1, 3, 12, 0, 0])\n",
+    "        array = [1, 0]\n",
+    "        solution.move_zeroes(array)\n",
+    "        assert_equal(array, [1, 0])\n",
+    "        array = [0, 1]\n",
+    "        solution.move_zeroes(array)\n",
+    "        assert_equal(array, [1, 0])\n",
+    "        array = [0]\n",
+    "        solution.move_zeroes(array)\n",
+    "        assert_equal(array, [0])\n",
+    "        array = [1]\n",
+    "        solution.move_zeroes(array)\n",
+    "        assert_equal(array, [1])\n",
+    "        array = [1, 1]\n",
+    "        solution.move_zeroes(array)\n",
+    "        assert_equal(array, [1, 1])\n",
+    "        print('Success: test_move_zeroes')\n",
+    "\n",
+    "\n",
+    "def main():\n",
+    "    test = TestMoveZeroes()\n",
+    "    test.test_move_zeroes()\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_move_zeroes\n"
+     ]
+    }
+   ],
+   "source": [
+    "%run -i test_move_zeroes.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": "3.4.3"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 0
+}
diff --git a/online_judges/move_zeroes/test_move_zeroes.py b/online_judges/move_zeroes/test_move_zeroes.py
new file mode 100644
index 0000000..f968699
--- /dev/null
+++ b/online_judges/move_zeroes/test_move_zeroes.py
@@ -0,0 +1,36 @@
+from nose.tools import assert_equal, assert_raises
+
+
+class TestMoveZeroes(object):
+
+    def test_move_zeroes(self):
+        solution = Solution()
+        assert_raises(TypeError, solution.move_zeroes, None)
+        array = [0, 1, 0, 3, 12]
+        solution.move_zeroes(array)
+        assert_equal(array, [1, 3, 12, 0, 0])
+        array = [1, 0]
+        solution.move_zeroes(array)
+        assert_equal(array, [1, 0])
+        array = [0, 1]
+        solution.move_zeroes(array)
+        assert_equal(array, [1, 0])
+        array = [0]
+        solution.move_zeroes(array)
+        assert_equal(array, [0])
+        array = [1]
+        solution.move_zeroes(array)
+        assert_equal(array, [1])
+        array = [1, 1]
+        solution.move_zeroes(array)
+        assert_equal(array, [1, 1])
+        print('Success: test_move_zeroes')
+
+
+def main():
+    test = TestMoveZeroes()
+    test.test_move_zeroes()
+
+
+if __name__ == '__main__':
+    main()
\ No newline at end of file