307. Range Sum Query

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:

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.

class NumArray {
    List<Integer> list = new ArrayList();
    
    public NumArray(int[] nums) {
        for(int i: nums) list.add(i);   
    }
    
    public void update(int i, int val) {
        list.set(i, val);
    }
    
    public int sumRange(int i, int j) {
        int res = 0;
        for(int m = i; m <= j; m++) res+=list.get(m);
        return res;
    }
}

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