Question 303 Range Sum Query – Immutable

Description of the question:

https://leetcode.com/problems/range-sum-query-immutable/

My Code:

class NumArray:

    def __init__(self, nums: List[int]):
        self.sums = [0]*len(nums)
        
        Sum = 0
        
        for i, j in enumerate(nums):
            Sum += j
            self.sums[i] = Sum
            

    def sumRange(self, i: int, j: int) -> int:
        if i ==0 :
            return self.sums[j]
        else:
            return self.sums[j]-self.sums[i-1]

Explanation: we store each sum into the object function OO.sums, then whenever we need to use it, we may be able to call this function and use it. This extra space used may save time from repeated calculation.