demo_backend_list_assessment.ipynb

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 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Demo for Backend-list-assessment"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Simple provided test() function used in main() to print\n",
    "# what each function returns vs. what it's supposed to return.\n",
    "def test(got, expected):\n",
    "    if got == expected:\n",
    "        prefix = ' OK '\n",
    "    else:\n",
    "        prefix = '  X '\n",
    "    print('{} got: {} expected: {}'.format(prefix, repr(got), repr(expected)))\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
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   "source": [
    "# Calls the above functions with interesting inputs.\n",
    "def test_list1():\n",
    "    print('match_ends')\n",
    "    test(match_ends(['aba', 'xyz', 'aa', 'x', 'bbb']), 3)\n",
    "    test(match_ends(['', 'x', 'xy', 'xyx', 'xx']), 2)\n",
    "    test(match_ends(['aaa', 'be', 'abc', 'hello']), 1)\n",
    "\n",
    "    print('front_x')\n",
    "    test(front_x(['bbb', 'ccc', 'axx', 'xzz', 'xaa']),\n",
    "         ['xaa', 'xzz', 'axx', 'bbb', 'ccc'])\n",
    "    test(front_x(['ccc', 'bbb', 'aaa', 'xcc', 'xaa']),\n",
    "         ['xaa', 'xcc', 'aaa', 'bbb', 'ccc'])\n",
    "    test(front_x(['mix', 'xyz', 'apple', 'xanadu', 'aardvark']),\n",
    "         ['xanadu', 'xyz', 'aardvark', 'apple', 'mix'])\n",
    "\n",
    "    print('sort_last')\n",
    "    test(sort_last([(1, 3), (3, 2), (2, 1)]),\n",
    "         [(2, 1), (3, 2), (1, 3)])\n",
    "    test(sort_last([(2, 3), (1, 2), (3, 1)]),\n",
    "         [(3, 1), (1, 2), (2, 3)])\n",
    "    test(sort_last([(1, 7), (1, 3), (3, 4, 5), (2, 2)]),\n",
    "         [(2, 2), (1, 3), (3, 4, 5), (1, 7)])\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "def test_list2():\n",
    "    print('remove_adjacent')\n",
    "    test(remove_adjacent([1, 2, 2, 3]), [1, 2, 3])\n",
    "    test(remove_adjacent([2, 2, 3, 3, 3]), [2, 3])\n",
    "    test(remove_adjacent([]), [])\n",
    "\n",
    "    print('linear_merge')\n",
    "    test(linear_merge(['aa', 'xx', 'zz'], ['bb', 'cc']),\n",
    "         ['aa', 'bb', 'cc', 'xx', 'zz'])\n",
    "    test(linear_merge(['aa', 'xx'], ['bb', 'cc', 'zz']),\n",
    "         ['aa', 'bb', 'cc', 'xx', 'zz'])\n",
    "    test(linear_merge(['aa', 'aa'], ['aa', 'bb', 'bb']),\n",
    "         ['aa', 'aa', 'aa', 'bb', 'bb'])\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## A. match_ends\n",
    "Given a list of strings, return the count of the number of\n",
    "strings where the string length is 2 or more and the first\n",
    "and last chars of the string are the same.\n",
    "Note: python does not have a ++ operator, but += works."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "def match_ends(words):\n",
    "    pass\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## B. front_x\n",
    "Given a list of strings, return a list with the strings\n",
    "in sorted order, except group all the strings that begin with 'x' first.\n",
    "e.g.\n",
    "```\n",
    "['mix', 'xyz', 'apple', 'xanadu', 'aardvark'] yields ['xanadu', 'xyz', 'aardvark', 'apple', 'mix']\n",
    "```\n",
    "Hint: this can be done by making 2 lists and sorting each of them\n",
    "before combining them."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "def front_x(words):\n",
    "    pass"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## C. sort_last\n",
    "Given a list of non-empty tuples, return a list sorted in increasing\n",
    "order by the last element in each tuple.\n",
    "e.g. \n",
    "```\n",
    "[(1, 7), (1, 3), (3, 4, 5), (2, 2)] yields [(2, 2), (1, 3), (3, 4, 5), (1, 7)]\n",
    "```\n",
    "Hint: use a custom key= function to extract the last element form each tuple."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "def sort_last(tuples):\n",
    "    pass\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## D.  remove_adjacent\n",
    "Given a list of numbers, return a list where\n",
    "all adjacent == elements have been reduced to a single element,\n",
    "so [1, 2, 2, 3] returns [1, 2, 3]. You may create a new list or\n",
    "modify the passed in list."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "def remove_adjacent(nums):\n",
    "    pass"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## E.  linear_merge\n",
    "Given two lists sorted in increasing order, create and return a merged\n",
    "list of all the elements in sorted order. You may modify the passed in lists.\n",
    "Ideally, the **solution should work in \"linear\" time**, making a single\n",
    "pass of both lists."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "def linear_merge(list1, list2):\n",
    "    result = []\n",
    "    pass"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "test_list1()\n",
    "test_list2()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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