LeetCode 1456: Maximum Number of Vowels in a Substring of Given Length (ACERS Guide)

Subtitle / Summary A standard fixed-window counting problem. This ACERS guide explains the sliding-window model, engineering use cases, and runnable multi-language solutions. Reading time: 10–12 min Tags: sliding window, string, fixed window SEO keywords: Maximum Number of Vowels, Sliding Window, Fixed Window Meta description: Fixed-window sliding count for maximum vowels with engineering applications. Target Readers LeetCode learners who want stable templates Engineers working on windowed metrics Anyone building real-time counters Background / Motivation Many engineering tasks ask: “What is the maximum count in any fixed-length window?” Recomputing every window is O(nk). Sliding window updates in O(1) per step, giving O(n). ...

January 20, 2026 · 7 min · map[name:Jeanphilo]

LeetCode 239: Sliding Window Maximum (Monotonic Queue ACERS Guide)

Title LeetCode 239: Sliding Window Maximum (Monotonic Queue ACERS Guide) Subtitle / Summary Sliding Window Maximum is the classic combo of sliding window + monotonic queue. This article follows the ACERS template with reusable engineering patterns and multi-language implementations. Estimated reading time: 12–15 minutes Tags: sliding window, monotonic queue, array SEO keywords: Sliding Window Maximum, monotonic queue, deque, O(n) Meta description: Monotonic-queue solution for Sliding Window Maximum with engineering practice and multi-language implementations. Target Readers People practicing LeetCode / Hot100 Mid-level developers who want a reusable “sliding window + monotonic queue” template Engineers working on real-time monitoring, log analytics, or risk control Background / Motivation Rolling-window maximum appears everywhere: latency monitoring, price spikes, temperature alerts, real-time smoothing, and many more. The brute-force approach recomputes max per window in O(nk), which is unacceptable for large n. The monotonic queue reduces it to O(n), making it the most practical engineering choice. ...

January 19, 2026 · 8 min · map[name:Jeanphilo]