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    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['0-->2']\n",
      "['0-->2', '4-->5']\n",
      "['0-->2', '4-->5', '7']\n",
      "['0-->2', '4-->5', '7']\n"
     ]
    }
   ],
   "source": [
    "\"\"\"\n",
    "Given a sorted integer array without duplicates,\n",
    "return the summary of its ranges.\n",
    "For example, given [0,1,2,4,5,7], return [\"0->2\",\"4->5\",\"7\"].\n",
    "\"\"\"\n",
    "\n",
    "input_array = [0,1,2,4,5,7]\n",
    "# input_array = [1,2,3,6,9,11,12,13,14,19,20]\n",
    "\n",
    "start=0\n",
    "result = []\n",
    "\n",
    "# i=0\n",
    "# while i <= len(input_array)-1:\n",
    "#     print(i, input_array[i])\n",
    "#     i = i+1\n",
    "\n",
    "\n",
    "while start < len(input_array):\n",
    "    \n",
    "    # initial end at start position     \n",
    "    end = start\n",
    "\n",
    "    # continue to move the end pointer if the gap is 1 with beside number\n",
    "    # only continue to move if index end+1 is inside array     \n",
    "    while end+1<len(input_array) and ((input_array[end+1] - input_array[end]) == 1):\n",
    "        end = end + 1\n",
    "\n",
    "    # add range to result after calculate     \n",
    "    if end!=start:\n",
    "        result.append(\"{0}-->{1}\".format(input_array[start], input_array[end]))\n",
    "        print(result)\n",
    "    else:\n",
    "        result.append(\"{0}\".format(input_array[start]))\n",
    "        print(result)\n",
    "        \n",
    "    # change to next range\n",
    "    start = end+1\n",
    "\n",
    "print(result)\n",
    "\n",
    "\n",
    "            "
   ]
  }
 ],
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