Here is my solution for the Range Sum Query problem, I thought it is efficient, but I got time limit exceed, Could anyone tell me how I can do better? I appreciate it.

'''

public class NumArray {

```
private int[] Nums;
public NumArray(int[] nums) {
Nums = nums;
}
public int sumRange(int i, int j) {
int Sum = 0;
if(i == j){
Sum = Nums[j];
}
else{
Sum = Nums[i] + sumRange(i+1,j);
}
return Sum;
}
```

}

'''