# LeetCode307 Range Sum Query-Mutable

## 描述

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

The update(i, val) function modifies nums by updating the element at index i to val.

Note:

1. The array is only modifiable by the update function.
2. You may assume the number of calls to update and sumRange function is distributed evenly.