# ljeng/cheat-sheet

Knowledge base for software engineers and research engineers

Repository: https://github.com/ljeng/cheat-sheet
Canonical: https://ross.abutalabs.com/products/cheat-sheet
Homepage: https://ljeng.github.io/cheat-sheet/
Language: Java
License Family: other
Topics: algorithms, system-design, operating-system, coding, data, data-structures, graphs, mathematics, recursion, sorting
Last push: 2026-07-27T00:31:09+00:00

## Health v2 (maintenance only)
Score: 75/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 94, release rhythm 35, longevity 100
- inputs: {"age_days": 2554, "days_push": 38, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1304, forks 156 (observed 2026-08-28T04:04:18.565278+00:00)

## What it is
A markdown-based knowledge base and cheat sheet covering coding, algorithms, data structures, system design, operating systems, and research engineering topics. It is published as a static reference site for software and research engineers.

## Use cases
- review algorithms before a coding interview
- study system design concepts like distributed systems and load balancers
- brush up on data structures such as trees, heaps, and hash maps
- learn operating system fundamentals like threads, locks, and scheduling
- reference graph algorithms like Dijkstra's and A*
- review probability and discrete math for research engineering

## When to choose
- you want a free, concise reference for CS fundamentals and interview prep
- you prefer markdown notes over interactive courses
- you need quick refreshers on algorithms, OS, and system design in one place

## When to avoid
- you need structured exercises, graded problems, or interactive learning
- you want a comprehensive textbook-depth treatment of any single topic
- you need guaranteed maintenance or a specific license for redistribution

## Facets
- artifact type: learning-resource
- maturity: active
- function: documentation, markdown, developer-tools
- domain: education, developer-tools, operating-systems, mathematics
- platform: cross-platform
- tags: cheat-sheet, interview-prep, system-design, data-structures, coding-interview, computer-science, study-notes, algorithms, web-server

## Member repositories
- ljeng/cheat-sheet (main) score 75

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:04:18.565278+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T04:51:08.738475+00:00, confidence not recorded.
  - readme: https://github.com/ljeng/cheat-sheet (fetched 2026-08-28T04:04:18.565278+00:00, sha 89a3842b0dba)
  - homepage: https://ljeng.github.io/cheat-sheet/ (fetched 2026-08-29T12:09:04.936315+00:00, sha 6ec4d19f8a8d)
- Data as of 2026-08-30T08:39:29.467469+00:00.