Find longest increasing contiguous subarray

Problem

You are given an integer array nums (length n).

Part 1

Find the length of the longest contiguous subarray that is strictly increasing (i.e., for every adjacent pair in the subarray, a[i] < a[i+1]).

Input: nums: int[]

Output: maxLen: int

Example:

• nums = [1, 2, 2, 3, 4] → longest strictly increasing contiguous subarray is [2,3,4] , so maxLen = 3 .

Follow-up

Now suppose you may modify (replace) the value of at most one element within a chosen contiguous subarray (replace it with any integer value you want) in order to make that subarray strictly increasing.

Return the maximum possible length of a contiguous subarray that can be made strictly increasing with ≤ 1 replacement.

Clarification/assumption (make explicit in interview): The replacement value is unconstrained (can be any integer), and you are asked only for the maximum achievable length.

Example idea:

• nums = [1, 5, 3, 4] → by replacing 5 with 2 , the whole array can become [1,2,3,4] , so answer is 4 .

Constraints (reasonable interview defaults)

• 1 <= n <= 2e5
• -1e9 <= nums[i] <= 1e9
• Aim for better than O(n^2) in the follow-up.