Data Structures and Algorithms in Java

A collection of abstract data types and algorithms initially based on the book Data Structures and Algorithms in Java by Adam Drozdek.

Prerequisites

• JDK 25 (earlier versions will not compile — preview features used)
• Maven 3.9+

Quick Start

# Build and run all tests
mvn clean test

# Run a single algorithm demo (e.g., QuickSort on random data)
mvn exec:java -Dexec.mainClass="org.drozdek.sorting.QuickSort" -q

# Generate Javadoc HTML
mvn javadoc:javadoc
# Open target/reports/apidocs/index.html in a browser

Tech Stack

Language	Java 25
Build	Maven 3.9+
Testing	JUnit Jupiter 6.0.3 (854 tests)
Coverage	JaCoCo 0.8.14 (90% instruction)
Static analysis	SonarCloud, Qodana, Checkstyle (Google)
CI/CD	GitHub Actions, Dependabot

Modules

• Sorting — Bubble, Bucket, Counting, Heap, Insertion, Merge, Quick, Selection, Shell + exercises (Closest Pair, Ternary Merge)
• Searching — Binary, Exponential, Fibonacci, Interpolation, Jump, Linear, Sentinel Linear, Ternary
• Trees — AVL, BST, Expression Tree, Heap, Max/Min Heap, Red-Black, Simple Tree, Splay, Static Binary, Suffix Tree, Trie, Threaded Tree + trees.applications (PrefixAutoComplete)
• Lists — Single/Double/Circular/Double Circular Linked Lists, Skip List + lists.applications (MusicPlaylist)
• Stacks — Adaptive, Array, Linked List, Stack with format + stacks.applications (BalancedBracketValidator)
• Queues — Array, Deque, Dynamic, Static, Heap + queues.applications (PrintSpooler)
• Graphs — Directed/Undirected/Weighted with Dijkstra, Prim-Jarnik, Kruskal, Floyd-Warshall (algorithms in graphs/algorithms/) + graphs.applications (BuildDependencyResolver)
• Hashing — Hash Table (separate chaining, auto-resize) + hashing.applications (UserSessionStore)
• Dynamic Programming — Fractional Knapsack, 0/1 Knapsack, Task Scheduling
• Recursion — Alphabetically Sorted, Majority Element, Towers of Hanoi

Build

mvn clean package
mvn test
mvn jacoco:report     # coverage report → target/site/jacoco/

Project Structure

src/main/java/org/drozdek/
├── commons/       utilities
├── dynamic/       knapsack and scheduling algorithms
├── graphs/        graph ADT, graph algorithms, and build dependency resolver
├── hashing/       hash table and in-memory session store
├── lists/         linked lists, skip list, and music playlist manager
├── queues/        queue implementations and FIFO print spooler
├── recursion/     recursive algorithms
├── searching/     search algorithms
├── sorting/       sorting algorithms
├── stacks/        stack implementations and balanced bracket validator
└── trees/         tree ADTs (BST, Trie, Suffix, etc.) and autocomplete engine

src/test/java/org/drozdek/
└── (mirrors main structure, 88 test files)

Documentation Conventions

All public APIs use modern markdown doc comments (///, JEP-467) following a consistent template (class-level includes Real-world use case and Complexity Analysis sections). Javadoc is generated via mvn javadoc:javadoc.

Each package contains a package-info.java summarizing its scope. See docs/report.md for a comprehensive architecture and change report.

License

MIT