Longest Subarray of 1s After Deleting One Element
Medium · Sliding Window · Array · Dynamic Programming · Sliding Window
Problem
Given a binary array nums, you must delete exactly one element from it.
Return the length of the longest run of consecutive 1s in what remains, or 0 if no 1 remains.
Examples
Input: nums = [1,0,1,1,0,1] Output: 3
Deleting the 0 at index 1 joins the 1 before it with the two 1s after it.
Input: nums = [1,1,1] Output: 2
One element must be deleted even though every element is a 1.
Input: nums = [0,0] Output: 0
There are no 1s at all.
Constraints
- 1 <= len(nums) <= 10^5
- nums[i] is 0 or 1
Approaches
- Try deleting every element — time O(n²), space O(1)
Follow-up
What if you may delete up to k elements, all of them zeros? The same window allows k zeros, and the answer becomes the window length minus the zeros it holds. If instead you flip a zero into a 1, nothing is removed and the full window length counts; see the use case "Longest run of 1s after turning one 0 into a 1".
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