Given a binary array nums, remove exactly one element from it. Return the length of the longest non-empty subarray consisting entirely of $1$'s in the resulting array. If no such subarray exists, return $0$.

Note: Exactly one element must always be deleted, even if all elements are $1$'s.

Constraints:

• $1 \leq$ nums.length $\leq 10^5$

• nums[i] is either $0$ or $1$

The key insight is that deleting exactly one element from the binary array is equivalent to allowing a sliding window to contain at most $1$ ...