303. Range sum query immutable

Given an integer array nums, handle multiple queries of the following type:

Calculate the sum of the elements of nums between indices left and right inclusive where left <= right.Implement the NumArray class:

NumArray(int[] nums) Initializes the object with the integer array nums. int sumRange(int left, int right) Returns the sum of the elements of nums between indices left and right inclusive (i.e. nums[left] + nums[left + 1] + … + nums[right]).
Example 1: Input [“NumArray”, “sumRange”, “sumRange”, “sumRange”] [[[-2, 0, 3, -5, 2, -1]], [0, 2], [2, 5], [0, 5]] Output [null, 1, -1, -3] Explanation NumArray numArray = new NumArray([-2, 0, 3, -5, 2, -1]); numArray.sumRange(0, 2); // return (-2) + 0 + 3 = 1 numArray.sumRange(2, 5); // return 3 + (-5) + 2 + (-1) = -1 numArray.sumRange(0, 5); // return (-2) + 0 + 3 + (-5) + 2 + (-1) = -3

• code

class NumArray:
    def __init__(self, nums: List[int]):
            self.nums = nums
            self.dp = [0]*len(nums)
            self.dp[0] = self.nums[0]
            for i in range(1,len(self.nums)):
                self.dp[i] = self.dp[i-1]+self.nums[i]

    def sumRange(self, left: int, right: int) -> int:
        return self.dp[right]-self.dp[left]+self.nums[left]

• code

class NumArray:
    def __init__(self, nums):
        self.cum_sum = list(itertools.accumulate([0] + nums))
        
    def sumRange(self, left, right):
        return self.cum_sum[right + 1] - self.cum_sum[left]

• code

class NumArray:

    def __init__(self, nums: List[int]):
        self.nums = nums
        

    def sumRange(self, left: int, right: int) -> int:
        return sum(self.nums[left:right+1])