PollingPriorityQueueViaHeapSort

This project is a continuation of the investigation into Democratic primary polling data. This repository contains a Java-based implementation for processing Democratic primary polling data sing principles of Object-Oriented Programming (OOP). The main objective is to utilize a heap to sort the candidates based on their polling numbers, thereby determining the leading candidates. Additionally, a Priority Queue is implemented.

Table of Contents

• Overview
• Classes
  • CSVReader Class
  • Candidate Class
  • Main Class
  • PriorityQueue Interface
  • ArrayHeap Class

Overview

The project focuses on:

• Reading CSV files containing polling data for presidential primary candidates.
• Sorting candidates using a heap data structure.
• Implementing a Priority Queue for managing the candidates.

Classes

CSVReader Class

• Functionality: Reads data from a CSV file and returns it as an ArrayList of String arrays.
• Methods:
  • read(FileReader csvFile): Reads the CSV file and returns an ArrayList of String arrays.
  • Uses a BufferedReader to read the file line by line.
  • • Provides a method to close the BufferedReader, close().

Candidate Class

• Attributes: Contains last name, full name, and percentage of each candidate.
• Methods:
  • Provides getter and setter methods for its attributes.
    • getLastName(): Returns the candidate's last name.
    • getFullName(): Returns the candidate's full name.
    • getPct(): Returns the candidate's percentage score.
    • setPct(double pct): Sets the candidate's percentage score.
  • Implements the Comparable interface to compare candidates based on their percentage and in case of a tie, the candidate’s last
    names are used. - compareTo(Candidate other)
  • toString(): Returns a string representation of the candidate.

Main Class

• Functionality:
  • Reads candidate data from CSV files specified in the command-line arguments.
  • Adds candidates to a priority queue (ArrayHeap) based on their percentage.
  • Prints the candidates in sorted order.
  • Demonstrates sorting an array of integers and characters using the ArrayHeap.
• Methods:
  • main(String[] args): Main method to run the program.

PriorityQueue Interface

Defines the basic operations for the priority queue

• Methods:
  • insert(E element): Inserts an element into the priority queue.
  • max(): Returns the maximum element in the priority queue.
  • removeMax(): Removes and returns the maximum element in the priority queue.
  • size(): Returns the number of elements in the priority queue.
  • isEmpty(): Checks if the priority queue is empty.

ArrayHeap Class

• Attributes: Contains a single instance variable, an ArrayList representing the heap.

• Constructor: ArrayHeap(): Initializes an empty priority queue/heap.

• Functionality:

  • Represents a max heap using an ArrayList.
  • Implements the PriorityQueue interface.
  • Provides methods for heap operations: insert, max, removeMax, bubbleUp, bubbleDown, and swap.
  • Provides methods for heap construction and sorting: buildMaxHeap and sort.
  • Overrides the toString method to print the heap in a tree-like format.

• Methods

  1. size(): Returns the number of elements in the heap.
  2. isEmpty(): Checks if the heap is empty and returns a boolean value.
  3. max(): Returns the maximum element in the heap without removing it.
  4. insert(E element): Inserts an element into the heap while maintaining the heap property.
  5. removeMax(): Removes and returns the maximum element in the heap, reorganizing the heap as necessary.

• Helper Methods:

  1. swap(int i, int j): Swaps the elements at the specified indices in the heap.
  2. parent(int i): Returns the index of the parent of the element at the specified index.
  3. leftChild(int i): Returns the index of the left child of the element at the specified index.
  4. rightChild(int i): Returns the index of the right child of the element at the specified index.
  5. bubbleUp(int i): Adjusts the position of an element in the heap by moving it upwards until the heap property is restored.

• Heapsort Related Methods:

  1. buildMaxHeap(ArrayList<E> array): Converts the given ArrayList into a max heap structure.
  2. sort(ArrayList<E> array): Uses the heap structure to sort the elements in the ArrayList in descending order.

• Override:

  1. toString(): Returns a string representation of the heap, displaying the elements in a structured format.