303. Range Sum Query - Immutable.ipynb

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    "Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive.\n",
    "\n",
    "Example:\n",
    "Given nums = [-2, 0, 3, -5, 2, -1]\n",
    "\n",
    "sumRange(0, 2) -> 1\n",
    "sumRange(2, 5) -> -1\n",
    "sumRange(0, 5) -> -3\n",
    "Note:\n",
    "You may assume that the array does not change.\n",
    "There are many calls to sumRange function."
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    "class NumArray(object):\n",
    "\n",
    "    def __init__(self, nums):\n",
    "        \"\"\"\n",
    "        :type nums: List[int]\n",
    "        \"\"\"\n",
    "        \n",
    "        self.nums=nums\n",
    "        for i in range(1,len(nums)):\n",
    "            self.nums[i]+=self.nums[i-1]\n",
    "\n",
    "    def sumRange(self, i, j):\n",
    "        \"\"\"\n",
    "        :type i: int\n",
    "        :type j: int\n",
    "        :rtype: int\n",
    "        \"\"\"\n",
    "        if i ==0:\n",
    "            return self.nums[j]\n",
    "        else:\n",
    "            return self.nums[j]-self.nums[i-1]\n"
   ]
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    "nums = [-2, 0, 3, -5, 2, -1]"
   ]
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   "source": [
    "obj = NumArray(nums)"
   ]
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    "obj.sumRange(2,5)"
   ]
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