Given an integer arraynums, find the sum of the elements between indicesiandj(i≤j), inclusive.

Example:

Given nums = [-2, 0, 3, -5, 2, -1]

sumRange(0, 2) -
>
 1
sumRange(2, 5) -
>
 -1
sumRange(0, 5) -
>
 -3

Note:

1. You may assume that the array does not change.
2. There are many calls to sumRange function.

class NumArray {

    int[] sums;
    public NumArray(int[] nums) {
        sums = new int[nums.length];
        if (nums != null && nums.length != 0) sums[0] = nums[0];

        for (int i = 1; i < nums.length; i++){
            sums[i] = nums[i] + sums[i - 1];
        }
    }

    public int sumRange(int i, int j) {
        return i == 0 ? sums[j] : sums[j] - sums[i - 1];
    }
}

/**
 * Your NumArray object will be instantiated and called as such:
 * NumArray obj = new NumArray(nums);
 * int param_1 = obj.sumRange(i,j);
 */