Posts on Robin Yang

The Core Patterns of Variable-Length Sliding Window: Longest & Shortest Subarrays

Fri, 16 Jan 2026 17:49:32 +0800

Previously, we explored the fixed-length sliding window technique, which typically involves sliding a window of constant size by one element at a time. For a detailed explanation, refer to the article —— 📝How to Solve Fixed-Length Sliding Window Problems.

Now, we encounter a new class of problems that also appear solvable with a sliding window approach, but with a crucial difference: the window size is variable.

Find the Longest Subarray

Given a string s, find the length of the longest substring without duplicate characters.

How to Integrate Swiper.js with Hugo Shortcodes

Sat, 10 Jan 2026 15:22:57 +0800

I’d like to add an image carousel / slider to my article. After some research, I found three common approaches:

Hardcoding HTML directly into Markdown (tedious and hard to maintain).
Using Hugo Modules (powerful but sometimes overkill for a simple slider).
Creating a Custom Shortcode (the perfect balance of flexibility and performance).

In this post, I’ll show you how I built a robust, reusable Swiper component using the Shortcode approach. This method keeps your Markdown clean while ensuring your site stays fast.

Reverse Thinking With Fixed-Length Sliding Window

Thu, 01 Jan 2026 17:22:51 +0800

We previously learned about the fixed-length sliding window technique, which typically involves sliding one element at a time. For a detailed explanation, refer to the article —— 📝How to Solve Fixed-Length Sliding Window Problems. Now, we encounter a new problem that also appears solvable with a sliding window, but with a slight twist🔗.

A Tricky Problem

There are several cards arranged in a row, and each card has an associated number of points. The points are given in the integer array cardPoints.

Math Typesetting in Hugo

Mon, 29 Dec 2025 14:45:52 +0800

Hugo supports LaTeX math rendering via third-party JavaScript libraries, with MathJax and KaTeX being the two most popular options. This guide uses KaTeX for its speed and lightweight design.

The implementation is simple: include the library in the <head> section. However, to optimize performance, we’ll load it conditionally—only on pages that actually need it.

$$ \color{#c7c3c3} { \begin{pmatrix} 1 & 2 \\ 3 & 4 \end{pmatrix} } $$

1. Create a Partial for KaTeX Assets

Create a new file at /layouts/partials/helpers/math.html and add the following:

How to Solve Fixed-Length Sliding Window Problems!

Wed, 24 Dec 2025 16:55:18 +0800

One Classic Problem

Given an integer array nums consisting of n elements, and an integer k, find the maximum sum of any contiguous subarray of size k.

Example:

Input: arr = [2, 1, 5, 1, 3, 2], k = 3

Output: 9

Explanation: Subarray [5, 1, 3] has the maximum sum 9

Constraints:

$n == nums.length$
$1 <= k <= n <= 10^5$
$-10^4 <= nums[i] <= 10^4$

Brute Force Approach

The simplest solution checks each subarray independently: