A ramp in an integer array `nums` is a pair `(i, j)` for which `i < j` and `nums[i] <= nums[j]`. The width of such a ramp is `j - i`.

Given an integer array `nums`, return the maximum width of a ramp in `nums`. If there is no ramp in `nums`, return `0`.

Example 1:

    Input: nums = [6,0,8,2,1,5]
    Output: 4
    Explanation: The maximum width ramp is achieved at (i, j) = (1, 5): nums[1] = 0 and nums[5] = 5.

Example 2:

    Input: nums = [9,8,1,0,1,9,4,0,4,1]
    Output: 7
    Explanation: The maximum width ramp is achieved at (i, j) = (2, 9): nums[2] = 1 and nums[9] = 1.

Constraints:

- `2 <= nums.length <= 5 * 104`
- `0 <= nums[i] <= 5 * 104`