Counting sort

CSort.ipynb

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   "execution_count": 2,
   "metadata": {},
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   "source": [
    "def c_sorted(a, ubound, key=lambda x: x):\n",
    "    counter = [0] * ubound\n",
    "    for ai in a:\n",
    "        counter[key(ai)] += 1\n",
    "    for i in range(1, ubound):\n",
    "        counter[i] += counter[i - 1]\n",
    "    b = [0] * len(a)\n",
    "    for ai in reversed(a):\n",
    "        counter[key(ai)] -= 1\n",
    "        b[counter[key(ai)]] = ai\n",
    "    return b"
   ]
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  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[2, 2, 3, 5, 8]"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
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   "source": [
    "c_sorted([2,5,3,8,2], 10)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[(2, 'a'), (2, 'e'), (3, 'c'), (5, 'b'), (8, 'd')]"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "c_sorted([(2, 'a'), (5, 'b'), (3, 'c'), (8, 'd'), (2, 'e')], 10, lambda x: x[0])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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