Circular Queue in Java

Generic Circular Queue implementation and queue-based algorithms

Java • Data Structures • Algorithms • Generics

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Overview

This repository provides a generic implementation of a Circular Queue (Ring Buffer) in Java together with several classical queue-based algorithms.

The project was developed as part of my study of Data Structures and Algorithms, with emphasis on algorithmic correctness, clean object-oriented design, and code readability.

The implementation uses an array-based circular indexing technique, allowing efficient queue operations without shifting elements after deletions.

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Features

• Generic implementation using Java Generics
• Array-based circular queue
• Constant-time enqueue and dequeue operations
• Clean object-oriented design
• Queue visualization
• Demonstration program
• Queue-based algorithmic applications

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Complexity Analysis

• enQueue() → O(1)
• deQueue() → O(1)
• top() → O(1)
• size() → O(1)
• isEmpty() → O(1)
• display() → O(n)

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Implemented Algorithms

Josephus Problem

Simulation of the classical Josephus elimination process using a circular queue.

Remove Item

Removes all occurrences of a specified element while preserving the order of the remaining queue.

Smallest Multiple Using Digits {0,9}

Computes the smallest positive multiple of a given integer that consists exclusively of the digits 0 and 9 using a queue-based breadth-first search strategy.

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Project Structure

src/
└── datastructures/
    └── queue/
        ├── CircularQueue.java
        ├── QueueAlgorithms.java
        └── Main.java

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Running the Project

Compile

javac src/datastructures/queue/*.java

Run

java -cp src datastructures.queue.Main

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Educational Objectives

This project demonstrates:

• Generic programming in Java
• Implementation of Abstract Data Types (ADTs)
• Circular array indexing
• Queue-based algorithmic techniques
• Algorithm complexity analysis
• Object-oriented software design

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Future Improvements

Potential future extensions include:

• Dynamic queue resizing
• Iterator support
• JUnit test suite
• Javadoc documentation
• Additional queue-based algorithms
• Performance benchmarking
• Maven/Gradle support

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License

This project is licensed under the MIT License.

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Developed by Anastasis Zachariou