Transaction Segments / Increasing Subarrays of Length K

Given transaction values over time, count contiguous segments of exactly length k whose values are strictly increasing from left to right. The prompt is a clean one-pass window / run-length counting problem from the 2026 Engineering OA. Requirements Input: an integer array transactionValues of length n and an integer k. transactionValues[i] is the transaction amount at time i. Count contiguous subarrays of exactly length k such that every adjacent pair is strictly increasing: transactionValues[i] < transactionValues[i+1] < ... < transactionValues[i+k-1]. Return the number of such segments. Notes Track the current length of the strictly-increasing run ending at each index. Every index with runLength >= k contributes one valid segment ending there. O(n) time, O(1) space. Edge cases: k = 1 makes every element a valid segment; duplicate adjacent values break the run because the condition is strict. Preparation Implement the run-length version and walk through why it counts exactly one length-k segment per valid ending index. Compare against the brute-force window check for small arrays to catch off-by-one errors.