Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add skills/arcadi4/nerdy/elementary-data-structuresnpx skills add Arcadi4/nerdy --skill elementary-data-structuresgit clone --depth 1 https://github.com/Arcadi4/nerdyWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00053 | $0.02890 |
| Opus 5 | $0.00026 | $0.01445 |
| Sonnet 5 | $0.00011 | $0.00578 |
| Haiku 4.5 | $0.00005 | $0.00289 |
Grade A, and why
elementary-data-structures scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 193 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Elementary Data Structures
Overview
Treat elementary data structures as representation contracts, not classroom containers. The core move is to name the operations, access pattern, ownership model, and boundary invariants before choosing arrays, lists, stacks, queues, or tree links.
Shared CLRS Conventions
Follow the parent clrs skill for mathematical formatting, formula-free headings, direct polished answers, and CLRS-wide answer style.
When to Use
- A problem asks for arrays, matrices, stacks, queues, linked lists, sentinels, rooted trees, or left-child/right-sibling representation.
- You need to implement or review a dynamic set with
SEARCH,INSERT,DELETE,MINIMUM,MAXIMUM,SUCCESSOR, orPREDECESSOR-like operations. - A design hinges on contiguity, locality, pointer chasing, deletion by pointer, circular-buffer wraparound, sentinel nodes, or parent/child/sibling navigation.
- A production discussion needs the lesson behind an undergraduate structure rather than a literal reimplementation.
Do not use this skill merely because code contains an array or list. Use ordinary language/library conventions unless representation choice, invariants, asymptotic behavior, or access patterns are central.
First Decision: What Contract Does the Structure Serve?
| Need | Prefer | Why |
|---|---|---|
| Random indexed access and dense storage | Contiguous array or vector | Index arithmetic is constant time and cache-friendly |
| Append/pop at one end | Dynamic array or stack abstraction | Simpler and more local than pointer nodes |
| FIFO bounded buffer | Circular array queue | Constant-time operations with fixed memory and explicit full/empty policy |
| Frequent middle splice with existing node handles | Doubly linked list | Pointer rewiring is constant time once the node is known |
| Search by key in an unordered small set | Array or list if tiny; otherwise a real dictionary | Elementary structures expose the cost; later chapters provide better dictionaries |
| Ordered enumeration from elementary structures only | Sorted array/list if updates are rare | Maintaining order shifts update cost somewhere |
| Variable-arity rooted tree | Child vectors or left-child/right-sibling | Choose by child iteration, random child access, memory, and parent navigation |
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2d ago First seen · 193 lines · 53 tokens per session scan A c2129b9583d9
elementary-data-structures is a skill published in the GitHub repository Arcadi4/nerdy (7 stars, last pushed 4mo ago), licensed MIT. It adds 53 tokens to every session and 2,890 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
Other skills, from other repositories
pptx
从论文、大纲或结构化文本生成 PowerPoint (.pptx) 演示文稿。Use when 用户需要把一篇论文/文章/大纲做成幻灯片、slides、演示文稿、PPT、deck。Don't use when 只需纯文本总结、生成 Word/PDF、或修改已有 pptx 的单个像素级样式。.
ai-style
当任务是用中文撰写或改写面向读者的文案（产品发布稿、公众号文章、邮件、README 等）， 或用户反馈文字「AI 味太重」「不像人写的」时，加载本 Skill。.
curly-quote-sft
Skill "curly-quote-sft" from bojieli/ai-agent-book, covering 中文技术文档符号与引用规范, 何时加载, 符号定义, 决策优先级 and 正反例约束.
triage
你是当前任务的分诊协调者。先识别用户的全部目标、顺序依赖和验收条件，再按 “事实检索 → 计算/执行 → 写作”顺序逐步请求切换到需要的专业能力。不要替专业 能力完成它的工作，也不要在信息缺失时臆造结果。.
writing
将共享历史中的已验证事实和计算结果整理成符合受众、格式与长度约束的成稿。.
research
用真实检索工具查找可追溯的事实、数据和来源。.