{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 65,
   "id": "amino-traveler",
   "metadata": {},
   "outputs": [],
   "source": [
    "from enum import Enum, auto\n",
    "class State(Enum):\n",
    "    StartString = auto()\n",
    "    ParseString = auto()\n",
    "    EscapeCharacter = auto()\n",
    "    EscapeHexadecimal = auto()\n",
    "    \n",
    "\n",
    "def count_characters(s):\n",
    "    cc = 0\n",
    "    cm = 0\n",
    "    ce = 0\n",
    "    state = State.StartString\n",
    "    \n",
    "    hexadecimal_count = 0\n",
    "    \n",
    "    for i in range(len(s)):\n",
    "        if s[i].isspace():\n",
    "            continue\n",
    "            \n",
    "        cc += 1\n",
    "        ce += 1\n",
    "        \n",
    "        if s[i] in ('\"', '\\\\'):\n",
    "            ce += 1\n",
    "            \n",
    "        if state is State.StartString:\n",
    "            if s[i] != '\"':\n",
    "                raise Exception('expecting \"')\n",
    "                \n",
    "            ce += 2\n",
    "            state = State.ParseString\n",
    "            continue\n",
    "            \n",
    "        if state is State.ParseString:\n",
    "            if s[i] == '\\\\':\n",
    "                state = State.EscapeCharacter\n",
    "                continue\n",
    "            if s[i] == '\"':\n",
    "                state = State.StartString\n",
    "                continue\n",
    "            cm += 1\n",
    "                \n",
    "        if state is State.EscapeCharacter:\n",
    "            if s[i] == 'x':\n",
    "                state = State.EscapeHexadecimal\n",
    "                hexadecimal_count = 0\n",
    "                continue\n",
    "            else:\n",
    "                state = State.ParseString\n",
    "                cm += 1\n",
    "                \n",
    "        if state is State.EscapeHexadecimal:\n",
    "            hexadecimal_count += 1\n",
    "            \n",
    "            if hexadecimal_count == 2:\n",
    "                state = State.ParseString\n",
    "                cm += 1\n",
    "                \n",
    "    return cc, cm, ce"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 66,
   "id": "selective-label",
   "metadata": {},
   "outputs": [],
   "source": [
    "import import_ipynb\n",
    "import helper\n",
    "s = helper.read_file('2015_8.txt')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 67,
   "id": "documented-silence",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1371\n",
      "2117\n"
     ]
    }
   ],
   "source": [
    "cc, cm, ce = count_characters(s)\n",
    "print(cc - cm)\n",
    "print(ce - cc)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "published-incident",
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
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   "display_name": "Python 3",
   "language": "python",
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  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
   "version": "3.9.2"
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  "title": "Matchsticks"
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