Maximum Width Ramp

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`