public NumArray(int[] nums) {
if (nums == null || nums.length == 0) {
for (int i = 0; i < size; i++) {
bit.update(i + 1, nums[i]);
public void update(int i, int val) {
bit.update(i + 1, val - nums[i]);
public int sumRange(int i, int j) {
return bit.query(j + 1) - bit.query(i);
public void update (int index, int val) {
while (index < sums.length) {
public int query(int index) {
* Your NumArray object will be instantiated and called as such:
* NumArray obj = new NumArray(nums);
* int param_2 = obj.sumRange(i,j);