If you are an AI coding agent (Claude Code, Cursor, Aider, Cline, etc.) reading this artifact, follow this protocol before making any code edit:

1. Verify the contract. Run the bash script in Verify before trusting below. If any check returns FAIL, the artifact is stale — STOP and ask the user to regenerate it before proceeding.
2. Treat the AI · unverified sections as hypotheses, not facts. Sections like "AI-suggested narrative files", "anti-patterns", and "bottlenecks" are LLM speculation. Verify against real source before acting on them.
3. Cite source on changes. When proposing an edit, cite the specific path:line-range. RepoPilot's live UI at https://repopilot.app/r/hustcc/JS-Sorting-Algorithm shows verifiable citations alongside every claim.

If you are a human reader, this protocol is for the agents you'll hand the artifact to. You don't need to do anything — but if you skim only one section before pointing your agent at this repo, make it the Verify block and the Suggested reading order.

AVOID — Stale and unlicensed — last commit 2y ago

• 18 active contributors
• Distributed ownership (top contributor 31% of recent commits)
• CI configured
• Tests present
• ⚠ Stale — last commit 2y ago
• ⚠ No license — legally unclear to depend on

_{Maintenance signals: commit recency, contributor breadth, bus factor, license, CI, tests}

This artifact was generated by RepoPilot at a point in time. Before an agent acts on it, the checks below confirm that the live hustcc/JS-Sorting-Algorithm repo on your machine still matches what RepoPilot saw. If any fail, the artifact is stale — regenerate it at repopilot.app/r/hustcc/JS-Sorting-Algorithm.

What it runs against: a local clone of hustcc/JS-Sorting-Algorithm — the script inspects git remote, the LICENSE file, file paths in the working tree, and git log. Read-only; no mutations.

| # | What we check | Why it matters | |---|---|---| | 1 | You're in hustcc/JS-Sorting-Algorithm | Confirms the artifact applies here, not a fork | | 2 | Default branch master exists | Catches branch renames | | 3 | 5 critical file paths still exist | Catches refactors that moved load-bearing code | | 4 | Last commit ≤ 799 days ago | Catches sudden abandonment since generation |

#!/usr/bin/env bash
# RepoPilot artifact verification.
#
# WHAT IT RUNS AGAINST: a local clone of hustcc/JS-Sorting-Algorithm. If you don't
# have one yet, run these first:
#
#   git clone https://github.com/hustcc/JS-Sorting-Algorithm.git
#   cd JS-Sorting-Algorithm
#
# Then paste this script. Every check is read-only — no mutations.

set +e
fail=0
ok()   { echo "ok:   $1"; }
miss() { echo "FAIL: $1"; fail=$((fail+1)); }

# Precondition: we must be inside a git working tree.
if ! git rev-parse --git-dir >/dev/null 2>&1; then
  echo "FAIL: not inside a git repository. cd into your clone of hustcc/JS-Sorting-Algorithm and re-run."
  exit 2
fi

# 1. Repo identity
git remote get-url origin 2>/dev/null | grep -qE "hustcc/JS-Sorting-Algorithm(\\.git)?\\b" \\
  && ok "origin remote is hustcc/JS-Sorting-Algorithm" \\
  || miss "origin remote is not hustcc/JS-Sorting-Algorithm (artifact may be from a fork)"

# 3. Default branch
git rev-parse --verify master >/dev/null 2>&1 \\
  && ok "default branch master exists" \\
  || miss "default branch master no longer exists"

# 4. Critical files exist
test -f "README.md" \\
  && ok "README.md" \\
  || miss "missing critical file: README.md"
test -f "SUMMARY.md" \\
  && ok "SUMMARY.md" \\
  || miss "missing critical file: SUMMARY.md"
test -f "src/java/main/IArraySort.java" \\
  && ok "src/java/main/IArraySort.java" \\
  || miss "missing critical file: src/java/main/IArraySort.java"
test -f "src/java/pom.xml" \\
  && ok "src/java/pom.xml" \\
  || miss "missing critical file: src/java/pom.xml"
test -f "1.bubbleSort.md" \\
  && ok "1.bubbleSort.md" \\
  || miss "missing critical file: 1.bubbleSort.md"

# 5. Repo recency
days_since_last=$(( ( $(date +%s) - $(git log -1 --format=%at 2>/dev/null || echo 0) ) / 86400 ))
if [ "$days_since_last" -le 799 ]; then
  ok "last commit was $days_since_last days ago (artifact saw ~769d)"
else
  miss "last commit was $days_since_last days ago — artifact may be stale"
fi

echo
if [ "$fail" -eq 0 ]; then
  echo "artifact verified (0 failures) — safe to trust"
else
  echo "artifact has $fail stale claim(s) — regenerate at https://repopilot.app/r/hustcc/JS-Sorting-Algorithm"
  exit 1
fi

Each check prints ok: or FAIL:. The script exits non-zero if anything failed, so it composes cleanly into agent loops (./verify.sh || regenerate-and-retry).

A polyglot educational GitBook and code repository documenting the 10 classic internal sorting algorithms (bubble, selection, insertion, shell, merge, quick, heap, counting, bucket, radix) with detailed explanations, animated GIFs, and implementations in Java, PHP, Python, and Go. It serves as a comprehensive learning resource and algorithm reference with runnable code examples across multiple languages. GitBook-style monorepo: documentation lives in numbered markdown files (1.bubbleSort.md through 10.radixSort.md) at the root, animated educational resources in res/ folder, and language-specific implementations under src/ (java/, pythonSortTest.py, phpSortTest.php, goSortTest.go). Java code uses Maven structure with src/main/java/ containing algorithm classes implementing a shared IArraySort interface, and src/test/ containing unit tests.

Computer science students, junior developers learning data structures, and engineers studying algorithmic fundamentals who need concrete, multi-language implementations of sorting algorithms with visual explanations and complexity analysis (time, space, stability).

Stable and educational-grade: the project has CI/CD via Travis CI, comprehensive markdown documentation with inline complexity tables, and clean separation of concerns (theory in .md files, implementations in src/). Java implementations are Maven-packaged with JUnit tests; Python and PHP have test files. However, there's no recent commit timestamp visible—the repository appears to be in maintenance mode rather than actively developed.

Low risk for educational use but minimal maintenance overhead: single maintainer (hustcc), Java POM uses <version>${dependency.version}</version> set to LATEST which can cause reproducibility issues, and no evidence of recent updates to implementations or dependencies. The project is stable enough for reference but unlikely to track modern language versions quickly.

The repository appears to be in a steady state focused on educational content preservation. No active PR or milestone data is visible in the provided file listing. The project likely receives occasional contributions adding translations or algorithm implementations in new languages, but primary development momentum is not evident.

Clone the repository and explore by language: git clone https://github.com/hustcc/JS-Sorting-Algorithm.git && cd JS-Sorting-Algorithm. For Java implementations: cd src/java && mvn clean test to run unit tests. For Python: python src/pythonSortTest.py. For Go: go run src/goSortTest.go. Read the markdown files (1.bubbleSort.md–10.radixSort.md) in order starting with 1.bubbleSort.md for theory-first learning.

Daily commands: Java: cd src/java && mvn clean compile && mvn test. Python: cd src && python pythonSortTest.py. PHP: cd src && php phpSortTest.php. Go: cd src && go run goSortTest.go. All are command-line, no server startup required—each produces console output verifying algorithm correctness.

• README.md — Entry point documenting all 10 sorting algorithms, their complexity, stability, and learning progression—essential context for understanding the repo's scope and structure.
• SUMMARY.md — GitBook table of contents mapping all markdown learning materials to their corresponding algorithm implementations across languages.
• src/java/main/IArraySort.java — Common interface defining the contract all sorting implementations must follow—critical abstraction for understanding the codebase architecture.
• src/java/pom.xml — Maven build configuration and project metadata; only build file in repo managing Java implementation compilation and testing.
• 1.bubbleSort.md — First algorithm documentation serving as template for all 9 subsequent markdown files; establishes pedagogical pattern and explanation format.
• src/java/main/QuickSort.java — Most complex sorting implementation (O(n log n) average case); representative of advanced algorithm pattern used throughout codebase.

• IArraySort interface (Java) — Defines contract: sort(int[] array) must reorder in-place or return sorted copy; enables polymorphic testing
  • Failure mode: If interface changes, all 10 implementations and test suite break; strict backward-compatibility required
• ArraySortTest validation harness (JUnit 4) — Executes all implementations against identical test cases (empty, single, sorted, reverse, duplicates); catches algorithmic bugs early
  • Failure mode: Missing test coverage allows incorrect implementations to pass; tests must evolve with new algorithms
• Markdown learning materials (Markdown + GitBook) — Explains algorithm intuition, walks through pseudocode execution, analyzes time/space complexity, compares stability; primary content
  • Failure mode: Pedagogical errors or outdated complexity analysis mislead learners; community review required
• Multi-language test suite (Python, PHP, Go) — Validates same algorithms work identically in Java, Python, PHP, Go; ensures algorithms transcend language
  • Failure mode: Language-specific bugs (off-by-one in loops, type coercion) can break single implementation without surfacing in CI

Add a new sorting algorithm (e.g., Cocktail Sort)

1. Create new markdown chapter explaining algorithm: copy 1.bubbleSort.md structure with complexity analysis, pseudocode, and comparison table (11.cocktailSort.md)
2. Implement interface in Java with class naming convention (src/java/main/CocktailSort.java)
3. Add test case verifying the implementation against standard test arrays (src/java/test/ArraySortTest.java)
4. Update SUMMARY.md to include new chapter in the outline (SUMMARY.md)
5. Implement equivalent sorting logic in Python, PHP, and Go test files for polyglot validation (src/pythonSortTest.py)

Add visualization for an algorithm

1. Create animated GIF showing step-by-step execution using tool like algorithm-visualizer or custom script (res/cocktailSort.gif)
2. Reference the GIF in the corresponding markdown chapter using standard image markdown syntax (11.cocktailSort.md)
3. Ensure GIF filename matches naming pattern: lowercase algorithm name + 'Sort.gif' (res/)

Add sorting implementation in a new language (e.g., C++)

1. Create new test harness following pattern of pythonSortTest.py with all 10 algorithm implementations (src/cppSortTest.cpp)
2. Ensure test suite validates correctness by checking sorted output matches expected results (src/cppSortTest.cpp)
3. Update README language implementation status and add to CI pipeline via .travis.yml if needed (README.md)

• GitBook + Markdown — Enables collaborative multi-language documentation with version control; free hosting and search; separates pedagogy from code
• Java + Maven — Primary implementation language providing reference implementations; Maven manages dependencies and standardizes build; JUnit enables repeatable validation
• Polyglot test files (Python/PHP/Go) — Demonstrates sorting algorithms are language-agnostic concepts; allows developers to learn algorithm in their preferred language
• Travis CI — Automated testing ensures all implementations remain correct as documentation evolves; catches regressions across platforms

• Teaching all 10 algorithms sequentially rather than grouping by complexity class

  • Why: Pedagogical progression builds intuition; reader can implement simple algorithms first before tackling divide-and-conquer
  • Consequence: Reading order matters; skipping chapters may leave knowledge gaps; but provides natural learning difficulty curve

• Using integer arrays as sole data structure rather than generic comparable types

  • Why: Simplifies code and reduces cognitive load for learners; focuses on algorithm mechanics not type systems
  • Consequence: Cannot directly sort objects or custom types; implementations must be adapted; educational value maximized at cost of production realism

• Maintaining separate implementations per language rather than transpiling or code generation

  • Why: Each language gets idiomatic, readable implementations; learners see language-specific best practices
  • Consequence: Code duplication requires synchronizing logic across 4+ languages; testing burden increases; but avoids artificial abstractions

• Does not provide production-ready sorting library (use language built-ins: Arrays.sort, sorted(), etc.)
• Does not cover external sorting or memory-constrained environments
• Does not implement parallel/concurrent sorting algorithms
• Does not optimize for real-world datasets (presorted, nearly-sorted, or heavily duplicated data)
• Does not provide interactive online visualization platform (only static markdown + GIFs)

Maven POM uses <version>${dependency.version}</version> set to LATEST for JUnit—this breaks reproducible builds; pin JUnit to a specific version (e.g., 4.13.2). The project name in POM is 'sort' (groupId: com.corning) but repo is 'JS-Sorting-Algorithm'—this mismatch is cosmetic but confusing. No explicit Java source/target for Go code; Go test file (goSortTest.go) uses no visible package structure, so running go run directly without a go.mod file may fail on modern Go versions. Python and PHP tests are not integrated into CI, so they may silently drift from Java implementations.

• In-place vs. Out-of-place sorting — This repo explicitly categorizes algorithms by space complexity (In-place uses O(1) extra memory like quicksort, out-of-place uses O(n) like merge sort); critical for choosing algorithms in memory-constrained environments
• Sorting stability — The repo's README highlights which algorithms preserve relative order of equal elements (bubble, insertion, merge, radix are stable; quick, heap, shell are not); essential for data where secondary sort keys matter
• Divide-and-conquer strategy — Merge sort and quick sort use this pattern; understanding this paradigm helps generalize beyond sorting to many other algorithms (binary search, FFT)
• Comparison-based vs. non-comparison sorting — Counting sort, bucket sort, and radix sort (sections 8-10) don't rely on element comparison; they can beat O(n log n) lower bound under specific conditions on data range and distribution
• Gap sequence in Shell sort — Shell sort (section 4) generalizes insertion sort with diminishing gaps; the choice of gap sequence (3-smooth, Knuth, Sedgewick) directly affects O(n^(1+ε)) complexity; shows algorithm performance is not deterministic from pseudocode alone
• Pivot selection in quicksort — Quick sort's O(n log n) average case depends on pivot choice; this repo likely demonstrates naive first-element pivot, but production versions use median-of-three or random selection to avoid O(n²) worst case
• Radix sort digit extraction and LSD vs. MSD — Radix sort (section 10) achieves O(d*n) by processing digits; understanding least-significant-digit vs. most-significant-digit extraction clarifies why it's linear and how to adapt it to strings or negative numbers

• TheAlgorithms/Java — Parallel sorting algorithm implementations in pure Java with extensive test coverage; directly comparable implementations and additional algorithms beyond the classic 10
• trekhleb/javascript-algorithms — Comprehensive algorithm compendium in JavaScript (despite this repo's name, it now covers multiple languages); similar educational goal with visual explanations and polyglot implementations
• algorithm-visualizer/algorithm-visualizer — Interactive web-based visualization of sorting algorithms in real-time; complements this repo's static GIFs with dynamic step-through learning
• jvm-profiling-benchmarks/sorting-benchmarks — Performance microbenchmarks comparing Java sorting implementations; relevant for understanding how the textbook algorithms perform in practice on real JVMs

To work on one of these in Claude Code or Cursor, paste: Implement the "<title>" PR idea from CLAUDE.md, working through the checklist as the task list.

Add comprehensive multi-language test suite with unified test runner

The repo has sorting implementations in Java, Python, Go, and PHP (src/pythonSortTest.py, src/goSortTest.go, src/phpSortTest.php, src/java/test/ArraySortTest.java) but tests are scattered and not integrated. Create a unified test harness that validates all implementations across languages produce identical sorted output, enabling contributors to verify correctness across the entire codebase.

• [ ] Create src/test_runner.py that orchestrates Java (via Maven), Python, Go, and PHP test execution
• [ ] Add test data generator in src/ with edge cases (empty arrays, single element, duplicates, negative numbers, large datasets)
• [ ] Update .travis.yml to run the unified test suite, ensuring all language implementations pass before merge
• [ ] Document test execution in README.md with language-specific setup requirements

Add JavaScript/TypeScript implementation with corresponding tests

The repo is named 'JS-Sorting-Algorithm' but has no JavaScript implementations in src/, only documentation in markdown files. Add production-ready JavaScript implementations to match the repo's identity and provide the most accessible language for web developers.

• [ ] Create src/javascript/ directory with implementations for all 10 algorithms matching Java/Python structure (src/javascript/bubbleSort.js, etc.)
• [ ] Create src/javascript/test/sortTest.js using Jest or Node's built-in test runner, mirroring src/java/test/ArraySortTest.java
• [ ] Add package.json in src/javascript/ with test script and add to .travis.yml for CI
• [ ] Update README.md to document JavaScript implementations and installation instructions

Add visualization/animation data export feature for algorithm comparison

The repo contains GIF visualizations in res/ (bubbleSort.gif, quickSort.gif, etc.) but no code generates them. Add a data export feature that outputs step-by-step array state changes during sorting, enabling contributors to generate visualizations and compare algorithm behavior empirically.

• [ ] Create src/java/main/SortStepTracer.java interface that wraps comparators to log array state at each swap/comparison
• [ ] Modify existing sort implementations in src/java/main/ to use StepTracer and export JSON/CSV showing: step number, elements swapped, operation count, array state
• [ ] Add src/python/sort_visualizer.py that generates similar step-by-step data for Python implementations
• [ ] Document the feature in SUMMARY.md with example output showing how to regenerate/verify the GIF animations

• Add missing test files for PHP and Python to the CI/CD pipeline (.travis.yml currently only shows Java—integrate python src/pythonSortTest.py and php src/phpSortTest.php into the build) and document how to run them in the README.
• Create a missing implementation: the repo covers 10 algorithms but skips Cocktail Shaker Sort (bidirectional bubble) and Comb Sort (shell's cousin)—add either as an 11th algorithm following the pattern: .md file with GIF, Java class implementing IArraySort, Python and PHP equivalents, and add to SUMMARY.md.
• Fix the Maven POM to pin JUnit version explicitly (replace LATEST with 4.13.2) and add Go module support (create src/go/go.mod) to make builds reproducible; document the required Go version in README.

This educational sorting algorithm repository has moderate security concerns primarily centered on dependency management and outdated tooling. The main issues are: (1) Dynamic dependency resolution using 'LATEST', (2) Outdated Maven plugin versions lacking security patches, (3) Committed build artifacts, and (4) Legacy Java version targeting. The codebase itself (sorting algorithms) has minimal attack surface and no apparent injection risks, SQLi, XSS, or secrets exposure. For an educational project, the security posture is acceptable but could be significantly improved through dependency pinning, plugin updates, and modern Java versions. No critical vulnerabilities detected that would pose immediate risk.

• High · Insecure Dependency Version Specification — src/java/pom.xml (line with <version>${dependency.version}</version>). The pom.xml uses '${dependency.version}LATEST' for junit dependency, which resolves to the latest available version at build time. This can introduce breaking changes and security vulnerabilities if a compromised or vulnerable version is released. Fix: Pin dependencies to specific tested versions. Replace 'LATEST' with a concrete version number (e.g., '4.13.2' for junit 4.x or '5.9.2' for junit 5.x). Implement dependency scanning tools like OWASP Dependency-Check or Snyk.
• Medium · Outdated Maven Plugins — src/java/pom.xml (plugin versions). The maven-compiler-plugin (3.7.0) and maven-surefire-plugin (2.20.1) are significantly outdated. These versions may contain security vulnerabilities and lack security patches available in newer versions. Fix: Update to latest stable versions: maven-compiler-plugin to 3.11.0+ and maven-surefire-plugin to 3.0.0+. Review Maven plugin security advisories regularly.
• Medium · Target Artifact in Version Control — src/java/target/sort-1.0-SNAPSHOT.jar. The compiled JAR artifact (src/java/target/sort-1.0-SNAPSHOT.jar) is committed to the repository. This defeats reproducible builds and may contain exploitable bytecode or dependencies. Fix: Add 'target/' directory to .gitignore. Rely on source builds and Maven artifact repositories. Remove the artifact from git history using 'git filter-branch' or 'git filter-repo'.
• Low · Insufficient Java Version Specification — src/java/pom.xml (source/target 1.8). The project targets Java 1.8 (released in 2014), which has reached end-of-life for most vendors. While this is an educational project, it doesn't follow current security best practices. Fix: For new projects, target Java 11 LTS or later (17 LTS recommended). This ensures access to modern security features and patches. Add Maven enforcer plugin to validate minimum Java version.
• Low · Missing Security Headers and CI/CD Configuration — .travis.yml. The .travis.yml file is present but configuration details are not shown. Travis CI should be configured with security-focused settings. No evidence of security scanning in CI/CD pipeline. Fix: Configure Travis CI to run: dependency vulnerability scanning (OWASP Dependency-Check), static code analysis (SonarQube), and code quality checks. Add security scanning for secrets using tools like git-secrets or TruffleHog.
• Low · Exposed Developer Email — src/java/pom.xml (developer email and url). Developer email address (corningsun@163.com) and personal URL are publicly exposed in the pom.xml developer section, increasing risk of targeted phishing attacks. Fix: Use a generic project email or omit personal contact information from the pom.xml. If necessary, use an organization-controlled email address instead of personal email.

LLM-derived; treat as a starting point, not a security audit.

• Open issues — current backlog
• Recent PRs — what's actively shipping
• Source on GitHub

Generated by RepoPilot. Verdict based on maintenance signals — see the live page for receipts. Re-run on a new commit to refresh.