3349. Adjacent Increasing Subarrays Detection I

Time: O(n)

Space: O(n)

Approach

Compute run lengths of strictly increasing subarrays; check adjacent runs ≥ k.

Key Techniques

Array problems involve manipulating elements stored in a contiguous block of memory. Key techniques include two-pointer traversal, prefix sums, sliding windows, and in-place partitioning. In C#, arrays are zero-indexed and fixed in size — use List<T> when you need dynamic resizing.

3349.cs

// Approach: Compute run lengths of strictly increasing subarrays; check adjacent runs ≥ k.
// Time: O(n) Space: O(n)

public class Solution
{
    public bool HasIncreasingSubarrays(IList<int> nums, int k)
    {
        int maxValidLength = 0;
        int previousLength = 0;
        int currentLength = 0;

        int n = nums.Count;

        for (int i = 0; i < n; i++)
        {
            currentLength++;

            if (i == n - 1 || nums[i] >= nums[i + 1])
            {
                maxValidLength = Math.Max(maxValidLength,
                                         Math.Max(currentLength / 2,
                                                  Math.Min(previousLength, currentLength)));

                previousLength = currentLength;
                currentLength = 0;
            }
        }

        return maxValidLength >= k;
    }
}

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