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   "source": [
    "# Quick Sort\n",
    "© 2021, Joe James"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 84,
   "metadata": {},
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   "source": [
    "import random\n",
    "\n",
    "def quick_sort(A):\n",
    "    quick(A, 0, len(A)-1)\n",
    "\n",
    "def quick(A, low, hi):\n",
    "    if low < hi:\n",
    "        p = partition(A, low, hi)\n",
    "        quick(A, low, p-1)\n",
    "        quick(A, p+1, hi)\n",
    "\n",
    "def get_pivot(A, low, hi):\n",
    "    return random.randrange(low, hi+1)\n",
    "    \n",
    "def partition(A, low, hi):\n",
    "    pivotIndex = get_pivot(A, low, hi)\n",
    "    pivotValue = A[pivotIndex]\n",
    "    A[pivotIndex], A[low] = A[low], A[pivotIndex]\n",
    "    border = low\n",
    "\n",
    "    for i in range(low, hi+1):\n",
    "        if A[i] < pivotValue:\n",
    "            border += 1\n",
    "            A[i], A[border] = A[border], A[i]\n",
    "    A[low], A[border] = A[border], A[low]\n",
    "\n",
    "    return (border)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Test Function\n",
    "Set a result flag. The j loop is used to perform 1000 test iterations. The next two lines create and shuffle list A of 100 integers. Then A is passed to our sorting function. The sorted result is compared to a sort using Python's sorted function. After 1000 iterations of the test, the result is printed."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 85,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Success\n"
     ]
    }
   ],
   "source": [
    "def test(func):\n",
    "    result = 'Success'\n",
    "    for j in range(1000):\n",
    "        A = [k for k in range(100)]\n",
    "        random.shuffle(A)\n",
    "        func(A)\n",
    "        if A != sorted(A):\n",
    "            result += 'Failed' + str(j)\n",
    "    print(result)\n",
    "test(quick_sort)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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