The width of a sequence is the difference between the maximum and minimum elements in the sequence.

Given an array of integers `nums`, return the sum of the widths of all the non-empty subsequences of `nums`. Since the answer may be very large, return it modulo `109 + 7`.

A subsequence is a sequence that can be derived from an array by deleting some or no elements without changing the order of the remaining elements. For example, `[3,6,2,7]` is a subsequence of the array `[0,3,1,6,2,2,7]`.

Example 1:

    Input: nums = [2,1,3]
    Output: 6
    Explanation: The subsequences are [1], [2], [3], [2,1], [2,3], [1,3], [2,1,3].
    The corresponding widths are 0, 0, 0, 1, 1, 2, 2.
    The sum of these widths is 6.

Example 2:

    Input: nums = [2]
    Output: 0

Constraints:

- `1 <= nums.length <= 105`
- `1 <= nums[i] <= 105`