You are given an integer array `nums`. The range of a subarray of `nums` is the difference between the largest and smallest element in the subarray.

Return the sum of all subarray ranges of `nums`.

A subarray is a contiguous non-empty sequence of elements within an array.

Example 1:

    Input: nums = [1,2,3]
    Output: 4
    Explanation: The 6 subarrays of nums are the following:
    [1], range = largest - smallest = 1 - 1 = 0
    [2], range = 2 - 2 = 0
    [3], range = 3 - 3 = 0
    [1,2], range = 2 - 1 = 1
    [2,3], range = 3 - 2 = 1
    [1,2,3], range = 3 - 1 = 2
    So the sum of all ranges is 0 + 0 + 0 + 1 + 1 + 2 = 4.

Example 2:

    Input: nums = [1,3,3]
    Output: 4
    Explanation: The 6 subarrays of nums are the following:
    [1], range = largest - smallest = 1 - 1 = 0
    [3], range = 3 - 3 = 0
    [3], range = 3 - 3 = 0
    [1,3], range = 3 - 1 = 2
    [3,3], range = 3 - 3 = 0
    [1,3,3], range = 3 - 1 = 2
    So the sum of all ranges is 0 + 0 + 0 + 2 + 0 + 2 = 4.

Example 3:

    Input: nums = [4,-2,-3,4,1]
    Output: 59
    Explanation: The sum of all subarray ranges of nums is 59.

Constraints:

- `1 <= nums.length <= 1000`
- `-109 <= nums[i] <= 109`

Follow-up: Could you find a solution with `O(n)` time complexity?