Project Euler Q17 - LO Man Hei

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   "source": [
    "### Q17\n",
    "If all the numbers from 1 to 1000 (one thousand) inclusive were written out in words, how many letters would be used?"
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    "number_word_map = {\n",
    "    1:\"one\",\n",
    "    2:\"two\",\n",
    "    3:\"three\",\n",
    "    4:\"four\",\n",
    "    5:\"five\",\n",
    "    6:\"six\",\n",
    "    7:\"seven\",\n",
    "    8:\"eight\",\n",
    "    9:\"nine\",\n",
    "    10:\"ten\",\n",
    "    11:\"eleven\",\n",
    "    12:\"twelve\",\n",
    "    13:\"thirteen\",\n",
    "    14:\"fourteen\",\n",
    "    15:\"fifteen\",\n",
    "    16:\"sixteen\",\n",
    "    17:\"seventeen\",\n",
    "    18:\"eighteen\",\n",
    "    19:\"nineteen\",\n",
    "    20:\"twenty\",\n",
    "    30:\"thirty\",\n",
    "    40:\"forty\",\n",
    "    50:\"fifty\",\n",
    "    60:\"sixty\",\n",
    "    70:\"seventy\",\n",
    "    80:\"eighty\",\n",
    "    90:\"ninety\",\n",
    "    100:\"hundred\",\n",
    "    1000:\"thousand\"\n",
    "}\n",
    "def num_to_word(num,sep=\" \"):\n",
    "    if num > 9999 or 1 > num:\n",
    "        print(\"out of range\")\n",
    "        return \"out of range\"\n",
    "    word_string_list = []\n",
    "    for key in [1000,100]:\n",
    "        if num >= key:\n",
    "            coeff = num // key\n",
    "            num -= coeff * key\n",
    "            word_string_list += [number_word_map[coeff],number_word_map[key]]\n",
    "    if word_string_list and num != 0:\n",
    "        word_string_list += [\"and\"]\n",
    "    for key in (*range(90,19,-10),*range(19,0,-1)):\n",
    "        if num >= key:\n",
    "            num -= key\n",
    "            word_string_list += [number_word_map[key]]\n",
    "    return sep.join(word_string_list)\n",
    "        "
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     "text": [
      "CPU times: user 900 µs, sys: 289 µs, total: 1.19 ms\n",
      "Wall time: 1.19 ms\n"
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       "21124"
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     "execution_count": 2,
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   "source": [
    "%%time\n",
    "sum([len(num_to_word(n,''))for n in range(1,1001)])"
   ]
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