Question

Priority Queue Demo

import java.util.*;

public class PriorityQueueDemo {
   public static void main(String[] args) {
       //TODO 1: Create a priority queue of Strings and assign it to variable queue1
      

       //TODO 2: Add Oklahoma, Indiana, Georgia, Texas to queue1
      
      

       System.out.println("Priority queue using Comparable:");
       //TODO 3: remove from queue1 all the strings one by one
       // with the "smaller" strings (higher priority) ahead of "bigger" strings.
       // print out each removed string and a space after the string.
      
      
      
       System.out.println();

       //TODO 4: Create a priority queue of Strings that will treat "bigger" as with higher priority.
       // Assign the queue to variable queue2.
      

       //TODO 5: Add Oklahoma, Indiana, Georgia, Texas to queue12

       System.out.println("\nPriority queue using Comparator:");
       //TODO 6: remove from queue2 all the strings one by one
       // with the "bigger" strings ahead of "smaller" strings.
       // print out each removed string and a space after the string.

       System.out.println();

       PriorityQueue<WorkOrder> queue3 = new PriorityQueue<>();
       queue3.offer(new WorkOrder(3, "Clean"));
       queue3.offer(new WorkOrder(2, "Build new structures"));
       queue3.offer(new WorkOrder(1, "Repair"));
       queue3.offer(new WorkOrder(4, "Preserve Energy"));

       System.out.println("\nWorkOrder Priority queue using Comparable:");
       while (queue3.size() > 0) {
           System.out.print(queue3.remove() + " ");
       }
       System.out.println();
   }
}

/**
This class encapsulates a work order with a priority.
*/
public class WorkOrder implements Comparable<WorkOrder>
{
   private int priority;
   private String description;

   /**
Constructs a work order with a given priority and description.
@param aPriority the priority of this work order
@param aDescription the description of this work order
   */
   public WorkOrder(int aPriority, String aDescription)
   {
       priority = aPriority;
       description = aDescription;
   }

   public String toString()
   {
       return "WorkOrder (" + priority + ", " + description + ")";
   }

   @Override
   public int compareTo(WorkOrder other) {
       // TODO: complete the method body.
       // Return a negative if this object's priority attribute is less than other's priority attribute
       // Return a positive if this object's priority attribute is greater than other's priority attribute
       // Return zero if this object's priority attribute is equal to other's priority attribute

       return 0;
   }
}

Answer 1

import java.util.*;

public class Main{
public static void main(String[] args) {
  
  

  
//TODO 1: Create a priority queue of Strings and assign it to variable queue1
PriorityQueue<String> queue1=new PriorityQueue<String>();
  
//TODO 2: Add Oklahoma, Indiana, Georgia, Texas to queue1
queue1.add("Oklahoma");
queue1.add("Indiana");
queue1.add("Georgia");
queue1.add("Texas");

  

System.out.println("Priority queue using Comparable:");
//TODO 3: remove from queue1 all the strings one by one
// with the "smaller" strings (higher priority) ahead of "bigger" strings.
// print out each removed string and a space after the string.
  
while (!queue1.isEmpty()) {
System.out.print(queue1.remove()+" ");
}
  
System.out.println();

Comparator<String> customComparator = new Comparator<String>() {
@Override
public int compare(String str1, String str2){
return str2.compareTo(str1);
}
};

//TODO 4: Create a priority queue of Strings that will treat "bigger" as with higher priority.
// Assign the queue to variable queue2.
PriorityQueue<String> queue2=new PriorityQueue<String>(customComparator);
  
//TODO 5: Add Oklahoma, Indiana, Georgia, Texas to queue12
queue2.add("Oklahoma");
queue2.add("Indiana");
queue2.add("Georgia");
queue2.add("Texas");

System.out.println("\nPriority queue using Comparator:");
//TODO 6: remove from queue2 all the strings one by one
// with the "bigger" strings ahead of "smaller" strings.
// print out each removed string and a space after the string.
while (!queue2.isEmpty()) {
System.out.print(queue2.remove()+" ");
}
  

System.out.println();

PriorityQueue<WorkOrder> queue3 = new PriorityQueue<>();
queue3.offer(new WorkOrder(3, "Clean"));
queue3.offer(new WorkOrder(2, "Build new structures"));
queue3.offer(new WorkOrder(1, "Repair"));
queue3.offer(new WorkOrder(4, "Preserve Energy"));

System.out.println("\nWorkOrder Priority queue using Comparable:");
while (queue3.size() > 0) {
System.out.print(queue3.remove() + " ");
}
System.out.println();
}
}

/**
This class encapsulates a work order with a priority.
*/
class WorkOrder implements Comparable<WorkOrder>
{
private int priority;
private String description;

/**
Constructs a work order with a given priority and description.
@param aPriority the priority of this work order
@param aDescription the description of this work order
*/
public WorkOrder(int aPriority, String aDescription)
{
priority = aPriority;
description = aDescription;
}

public String toString()
{
return "WorkOrder (" + priority + ", " + description + ")";
}

@Override
public int compareTo(WorkOrder other) {
// TODO: complete the method body.
// Return a negative if this object's priority attribute is less than other's priority attribute
// Return a positive if this object's priority attribute is greater than other's priority attribute
// Return zero if this object's priority attribute is equal to other's priority attribute
if(other.priority==priority){
return 0;
}
else if(priority<other.priority){
return -1;
}
else{
return 1;
}

}
}

Screenshot of code

//TODO 1: Create a priority queue of Strings and assign it to variable queue1 PriorityQueue<String> queue1=new PriorityQueue <String>(); //TODO 2: Add Oklahoma, Indiana, Georgia, Texas to queue1 queue1.add("Oklahoma"); queuel.add("Indiana"); queuel.add("Georgia"); queue1.add("Texas"); System.out.println("Priority queue using Comparable:"); //TODO 3: remove from queue1 all the strings one by one // with the "smaller" strings (higher priority) ahead of "bigger" strings. // print out each removed string and a space after the string. while (!queuel.isEmpty()) { System.out.print(queue1.remove()+" "); System.out.println(); Comparator<String> customComparator = new Comparator<String>() { @Override public int compare(String stri, String str2) { return str2.compare to str1); Je //TODO 4: Create a priority queue of Strings that will treat "bigger" as with higher priority. // Assign the queue to variable queue2. PriorityQueue <String> queue2=new PriorityQueue<String>(customComparator);

Constructs a work order with a given priority and description. @param aPriority the priority of this work order @param aDescription the description of this work order * public Workorder(int aPriority, String aDescription) priority = aPriority; description = aDescription; public String toString() return "Workorder (" + priority + ", " + description + ")"; @Override public int compare to WorkOrder other) { // TODO: complete the method body. // Return a negative if this object's priority attribute is less than other's priority att // Return a positive if this object's priority attribute is greater than other's priority // Return zero if this object's priority attribute is equal to other's priority attribute if(other priority=-priority){ return 0; else if(priority other priority){ return -1; else{ return 1;

Sample Output

Priority queue using Comparable: Georgia Indiana Oklahoma Texas Priority queue using Comparator: Texas Oklahoma Indiana Georgia Workorder Priority queue using Comparable: Workorder (1, Repair) Workorder (2, Build new structures) Workorder (3, Clean) Workorder (4, Preserve Energy) ... Program finished with exit code o Press ENTER to exit console.