Practice/Google/Leetcode 3350. Adjacent Increasing Subarrays Detection II

Leetcode 3350. Adjacent Increasing Subarrays Detection II

CodingOptional

Problem

You are given an array of integers. Your task is to find the maximum length k such that there exist two adjacent subarrays (one immediately following the other with no gap) where:

• Each subarray has exactly length k
• Both subarrays are strictly increasing (each element is greater than the previous one)

Return the maximum value of k that satisfies these conditions.

Requirements

1. Find two consecutive, non-overlapping subarrays of equal length k
2. Both subarrays must be strictly increasing
3. The second subarray must start immediately after the first ends
4. Return the maximum possible value of k

Constraints

• 2 ≤ nums.length ≤ 200,000
• -10^9 ≤ nums[i] ≤ 10^9
• The answer is guaranteed to be at least 1 (any single element is trivially increasing)
• Aim for O(n) or O(n log n) time complexity

Examples

Example 1:

Input: nums = [1, 2, 3, 4, 2, 3, 4, 5] Output: 3 Explanation: The subarray [1,2,3] (indices 0-2) and [4,2,3] starting at index 3... wait, that's not increasing. Let's check [2,3,4] (indices 4-6) and [4,5,...] - no that overlaps. Actually, [1,2,3] at indices 0-2 is not followed by another length-3 increasing array. The correct split is trickier - we need to analyze the maximal increasing runs carefully.

Example 2:

Input: nums = [1, 2, 3, 4, 5, 6] Output: 3 Explanation: We can use [1,2,3] (indices 0-2) and [4,5,6] (indices 3-5). Both are strictly increasing with length 3.

Example 3:

Input: nums = [5, 4, 3, 2, 1] Output: 1 Explanation: The array is decreasing, so no two adjacent elements are increasing. However, each single element is trivially a strictly increasing sequence of length 1, so k=1 is the answer.

Example 4:

Input: nums = [1, 2, 1, 2, 1, 2] Output: 1 Explanation: Only single-element subarrays work, so k=1.