A ramp in an integer array nums is defined as a pair of indices (i, j) such that i < j and nums[i] <= nums[j]. The width of such a ramp is j - i.

Given an integer array nums, find and return the maximum width of any ramp in nums. If no valid ramp exists, return $0$.

Constraints:

• $2 \leq$ nums.length $\leq 5 \times 10^4$ ...