{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Used: ['651', '774', '607']\n",
      "Now: 691\n"
     ]
    }
   ],
   "source": [
    "import os\n",
    "import random\n",
    "\n",
    "used = \"used.txt\"\n",
    "if not os.path.exists(used):\n",
    "    open(used, \"w+\").close()\n",
    "\n",
    "with open(used, \"r+\", encoding=\"utf8\") as f:\n",
    "    used_problems = f.readlines()\n",
    "    used_problems = [u.strip(\"\\n\") for u in used_problems]\n",
    "    print(\"Used:\", used_problems)\n",
    "\n",
    "    r = [i for i in range(1, 1040)]\n",
    "    r = [i for i in r if str(i) not in used_problems]\n",
    "    random.shuffle(r)\n",
    "    now = None\n",
    "    if len(r) == 0:\n",
    "        print(\"All done!\")\n",
    "        exit(0)\n",
    "    elif len(r) == 1:\n",
    "        now = r[0]\n",
    "    else:\n",
    "        now = random.choice(r)\n",
    "    print(\"Now:\", now)\n",
    "    f.write(str(now) + \"\\n\")"
   ]
  }
 ],
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