Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive.
The update(i, val) function modifies nums by updating the element at index i to val.
Example:
Given nums = [1, 3, 5] sumRange(0, 2) -> 9 update(1, 2) sumRange(0, 2) -> 8
Note:
<li>The array is only modifiable by the <i>update</i> function.</li>
<li>You may assume the number of calls to <i>update</i> and <i>sumRange</i> function is distributed evenly.</li>