Notes

package PQ;

import java.util.ArrayList;



public class PriorityQueue <T extends Comparable<T>> {

@SuppressWarnings({ "rawtypes", "unchecked" })
public static void main (String[] args)
{
PriorityQueue lista = new PriorityQueue();
lista.enqueue(10);
lista.enqueue(8);
lista.enqueue(30);
lista.enqueue(50);
lista.enqueue(5);

lista.enqueue(99);
lista.enqueue(40);

lista.print();

lista.dequeue();
lista.dequeue();

lista.print();

System.out.println("peek:" + lista.peek() + " size: " + lista.size() + " first: " +
lista.first + " sista: " + lista.last);

}

Node first;
Node last;
Integer nrOfElements;

public PriorityQueue ()
{
this.first = null;
this.last = null;
this.nrOfElements = 0;
}

@SuppressWarnings("unchecked")
void enqueue(T element)
{
if (this.first != null)
{
System.out.println(element.compareTo(this.first.data));
if(element.compareTo(this.first.data) < 0) //Om elementet vi stoppar in är mindre än första platsen
{
Node temp = this.first; //temp får värde på första platsen
//System.out.println(temp);
while(temp.next != null) //sålänge det finns något på andra platsen
{
temp = temp.next; //temp får värde på nästa plats
if((temp.data.compareTo(element) < 0 && temp.next.data.compareTo(element) >= 0))
{
Node tempNode = new Node(element, temp.next);
temp = new Node(temp.data, tempNode);
this.nrOfElements++;
break;
}
}
if (temp == this.last)
{
this.last.next = new Node(element, this.last.next.next);
//this.last = this.last.next;
this.nrOfElements++;
}
}
Node temp3 = this.first;
this.first = new Node(element, temp3);
}

else
{
this.first = new Node(element, this.first);
this.nrOfElements++;
}
}

void print() {
String result = "List:";
Node t = first;
while (t != null) {
result = result + ", " + t.data;
t = t.next;
}
System.out.println(result);
}

void dequeue()
{
this.first = this.first.next;
}

T peek()
{
return this.first.data;
}

int size()
{
return this.nrOfElements;
}

boolean isEmpty()
{
boolean returnValue;
if (this.nrOfElements == 0)
{
returnValue = true;
}
else
{
returnValue = false;
}
return returnValue;
}

private class Node
{
public T data;
public Node next;

public Node ()
{
this.data = null;
this.next = null;
}

public Node (T element) {
this.data = element;
this.next = null;
}

public Node (T element, Node nextNode)
{
this.data = element;
this.next = nextNode;
}
}

}