Leetcode-Question-303: Range Sum Query – Immutable

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

题目描述:
Range Sum Query – Immutable
Difficulty: Easy

Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive.

Example:
Given nums = [-2, 0, 3, -5, 2, -1]

sumRange(0, 2) -> 1
sumRange(2, 5) -> -1
sumRange(0, 5) -> -3

Note:
You may assume that the array does not change.
There are many calls to sumRange function.

解析: