An IRT-shaped practice score is not an IQ test
IntelligenceMax updates a learner estimate after every answer and displays it on the familiar IQ scale. The arithmetic resembles item response theory.…
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The Union‑Find Fellowship: Finding Your Tribe in Code
The Quest Begins (The "Why") I still remember the first time I stared at a LeetCode problem that asked me to count the number of islands in a grid. My…
# Understanding Backtracking Through a Tetris Optimizer in Go
When I first heard the term backtracking , it sounded like a complicated algorithm reserved for computer scientists. After spending the last couple of…
LeetCode 78. Subsets
Link https://leetcode.com/problems/subsets/description/ Problem Given an integer array nums of unique elements, return all possible subsets (the power…
Deterministic Wrong: Why a Viral Web Toy Must Be Wrong the Same Way Every Time
A calculator that gives you 2+2=7 and your friend 2+2=5 is just a broken calculator. Nobody shares it. Nobody argues about it. Nobody screenshots it a…
Building a Polymarket Trading Bot: Order Book Monitoring, Slippage Handling, and Position Sizing in Python
Why naive orders lose money on Polymarket Most people's first Polymarket bot places a market order and calls it done. That works fine on liquid, high-…
Solving Every CSES Problems in Rust - #1 Number Spiral
The constraints for x, y is 10^9, given these constraints the problem cannot be solved by actually building the spiral - but a static function with re…
Building SaarDB, Part 2: LSM Trees
In Part 1, SaarDB had two pieces: a Write Ahead Log (WAL) for durability, an in-memory map for serving reads and writes. That works as a starting poin…
How Reddit Stores Comment Trees and Ranks Hot Posts
Reddit looks simple and hides two genuinely hard problems. Comments nest arbitrarily deep, and a naive tree structure makes loading a busy thread slow…
Semantic Drift in LLMs: How Archetypal Attractors (Like “Goblin”) Emerge and How Structured Reflection Reduces Them
Large language models often develop recurring symbolic patterns — archetypes, metaphors, and memetic shortcuts — that appear across unrelated contexts…
Palette quantization notes: reducing colors without making an image muddy
I’ve been thinking about a small image-processing problem lately: how to reduce an image to a limited palette without making it look muddy. This comes…
From Turbo Pascal to TypeScript: A 35-Year-Old Maze Algorithm Comes Back to Life
In 1991, on a DOS machine with a BGI graphics driver, I wrote a small program that draw colored trees on screen. It wasn't meant to generate mazes. It…
How to Backtest a Trading Strategy with Python and EODHD API
Most backtests lie to you. Not intentionally. But they lie. You design a strategy, run it on historical data, and watch the returns look incredible. T…
The Binary Search Strikes Back: A Jedi's Guide to Finding Things Fast
The Quest Begins (The "Why") Honestly, I used to dread interview questions that started with “Given a sorted array…”. My first attempt was a clumsy li…
Every hand is solvable: engineering a block puzzle that never cheats
Block puzzles — the 8×8 "place three pieces, clear lines" genre — share a dirty secret: sometimes the game simply deals you pieces that cannot fit any…
Maximum Width of Binary Tree
Given the root of a binary tree, return the **## Problem Statement Given the root of a binary tree, return the maximum width of the tree. The width of…
Generating a Live Recap Before the Match Ends: Why Real-Time Recaps Are Hard
A highlight reel is a sequence of moments. A recap is a story. Producing a recap automatically while a match is still being played is a different and …
Vertical Order Traversal
leetcode.com Problem Statement Given the root of a binary tree, return its vertical order traversal . Rules: Nodes are grouped by their column (Horizo…
How to Validate an IBAN (MOD-97 Check Digit, Explained)
You typed your IBAN, hit send, and the bank threw it straight back: invalid IBAN . The number looks exactly right — same letters, same digits you copi…
Understanding the Luhn Algorithm: Why your browser knows a card number is invalid before the bank does
While making an online payment the other day, I accidentally mistyped my card number. The website rejected it immediately, even before there was any i…
Morris Pre Order Traversal
Problem Statement Given the root of a binary tree, return its preorder traversal. The challenge is to perform the traversal: Without Recursion Without…
Top View of Binary Tree | Level Order Traversal
Problem Statement Given the root of a binary tree, return the nodes visible when the tree is viewed from the top. For every horizontal distance (HD) ,…
Right View of a Binary Tree
leetcode.com Problem Statement Given the root of a binary tree, return the nodes visible when the tree is viewed from the right side. Only the last no…
Left View of a Binary Tree
leetcode.com Problem Statement Given the root of a binary tree, return the nodes visible when the tree is viewed from the left side. Only the first no…
Binary Tree PreOrder Traversal
leetcode.com Problem Statement Given the root of a binary tree, return its preorder traversal. Preorder Traversal follows: Root ↓ Left ↓ Right Brute F…
Segment Trees: The Matrix of Range Queries
The Quest Begins (The "Why") I still remember the first time I faced a problem that asked for the sum of numbers in a sub‑array, over and over again, …
Compare version numbers
Problem Statement Given two version strings: version1 version2 Each version consists of revisions separated by dots ( . ). Compare the two versions. R…
The Minecraft anvil is a tree-cost optimization problem in disguise
I fell down this rabbit hole because of a small, annoying moment in a survival game. I had a diamond pickaxe I liked, four enchanted books I wanted on…
Why Hijri Date Conversion Breaks Naive Math Formulas
If you search "convert Gregorian to Hijri" you'll find dozens of one-line formulas floating around StackOverflow, most of them some variant of hijriYe…
Z Function
Intuition The Z Algorithm is used to find all occurrences of a pattern in a text in linear time. The main idea is to avoid comparing the same characte…