Built By Sid

Algo
Products

12 real-world mini products built around LeetCode algorithm patterns. Each one is a complete loop: spec, build, publish. No shortcuts on the hard parts.

The Rule: build the core algorithm in a blank file. No AI.
12products to ship
01rule: no AI on the algorithm
languages — Go, Rust, Python
things to learn

The Why

Two birds,
one stone

I failed the last stage of a 6-stage interview because I didn't know algorithms well enough. That stung. But the industry is also changing — Google is moving toward AI-assisted interviews, and the question of what engineers actually need to know is genuinely open.

My take: we still need to problem solve organically. The shape of work is changing — we'll be building tiny systems, internal tooling, features of larger products — and for all of that we need to know when to prompt AI, when to write it ourselves, and how to judge the output.

So this project is my answer. I get to practice algorithms through building real products, and I get to ship things worth writing about. Kill two birds with one stone.

01

Algorithms through products

LeetCode patterns feel abstract in isolation. Building something real around them makes the pattern stick.

02

Honest constraint

The core algorithm gets built in a blank file with no AI. Everything else is fair game. The constraint is where the learning lives.

03

Build, learn, share

Every product gets a dev log on Substack. The writing forces clarity. The shipping forces completion.

04

Learning Go along the way

Most products are built in Go. Low supply chain risk, fast binaries, minimal deps. The language itself is part of the challenge.

The Catalogue

12 products,
ordered by interview relevance

01Go

Org Chart Explorer

BFS · DFS · Lowest Common Ancestor

02Go

Word Morph

BFS · Bidirectional BFS · A*

03Go

Kanban Snake

Stack · DAG · Topological Sort · Cycle Detection

04Rust

Link Vault

Trie · Union-Find · LRU Cache

05Go

Budget Pulse

Prefix Sums · Monotonic Stack · Binary Search

06Go

Type Racer Solo

Sliding Window · Two Pointers · Edit Distance DP

07Go

Focus Timer

Interval Merging · Greedy Scheduling · DP

08Go

Splitwise Lite

Greedy · Directed Graphs · Topological Sort

09Rust

Diff Tool

Edit Distance · LCS · Myers Diff

10Python

Sous Chef

Hash Maps · Sliding Window · BFS / DFS

11Rust

Pack It

0/1 Knapsack · Unbounded Knapsack · Multi-dim DP

12Go

DJ Mode

HashMap + Array Sync · Weighted Random · Stack

The Format

Every product,
same structure

The Technique

What the algorithm is and why it's hard. No hand-waving.

Algorithm Ladder

V1, V2, V3. Complexity grows with the product. Ship early, improve often.

The Constraint

The rule you honour to make the learning stick. No AI on the core algorithm.

The Self-Test

How you know your implementation is actually correct. Every product has one.

Follow Along

Dev logs on Substack

Every product gets a write-up. The thinking, the mistakes, the algorithm, the shipping. No polish theatre — just honest documentation of the build.

Read on Substack ↗