Range Sum Query - Immutable

Statement

You are given an integer array, nums, and you need to handle multiple queries of the following type:

• Query: Calculate the sum of elements in nums between indices i and j (inclusive), where i <= j.

Implement the NumArray class to support the following operations efficiently:

• Constructor (NumArray(int[] nums): Initializes the object with the integer array nums.

• int sum_range(int i, int j): Returns the sum of the elements of nums between indices i and j (inclusive), i.e., the sum of nums[i] + nums[i + 1] + ... + nums[j].

Constraints:

• $1 \leq$ nums.length $\leq 10^3$

• $-10^5 \leq$ nums[i] $\leq 10^5$

• $0 \leq$ i $\leq$ j $<$ nums.length

• At most, $10^3$ calls will be made to sum_range.

Examples