Hybrid Stack in Java

Generic Hybrid Stack implementation and stack-based algorithms

Java • Data Structures • Algorithms • Generics

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Overview

This repository provides a generic implementation of a Hybrid Stack in Java together with several stack-based algorithms.

The implementation combines the advantages of linked structures and fixed-size arrays by representing the stack as a linked list of array blocks. This hybrid approach reduces pointer overhead while maintaining dynamic growth.

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.

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Features

• Generic implementation using Java Generics
• Hybrid stack architecture (linked list of fixed-size arrays)
• Constant-time push and pop operations (amortized)
• Clean object-oriented design
• Stack visualization
• Demonstration program
• Stack-based algorithmic applications

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Complexity Analysis

• push() → O(1) (amortized)
• pop() → O(1) (amortized)
• top() → O(1)
• isEmpty() → O(1)
• display() → O(n)

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Implemented Algorithms

Remove Minimum (Using Queue)

Finds and removes all occurrences of the minimum element using only stack operations together with a helper queue.

Remove Minimum (Using Stack)

Finds and removes all occurrences of the minimum element using only stack operations together with a helper stack.

Compress

Compresses consecutive equal values into (frequency, value) pairs while preserving the original order of the stack.

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Project Structure

src/
└── datastructures/
    └── stack/
        ├── HybridStack.java
        ├── CircularQueue.java
        ├── StackAlgorithms.java
        └── Main.java

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Running the Project

Compile

javac src/datastructures/stack/*.java

Run

java -cp src datastructures.stack.Main

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Educational Objectives

This project demonstrates:

• Generic programming in Java
• Implementation of Abstract Data Types (ADTs)
• Hybrid memory organization
• Stack-based algorithmic techniques
• Algorithm complexity analysis
• Object-oriented software design

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Future Improvements

Potential future extensions include:

• Dynamic block resizing
• Iterator support
• JUnit test suite
• Javadoc documentation
• Additional stack-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