69 lines
1.8 KiB
Java
69 lines
1.8 KiB
Java
/*
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* A linked list is similar to an array, it holds values. However, links in a linked list do not have indexes.
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* With a linked list you do not need to predetermine it's size as it grows and shrinks as it is edited.
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* This is an example of a singly linked list. Elements can only be added/removed at the head/front of the list.
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*/
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class LinkedList{
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private Link head; //Head refers to the front of the list
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public LinkedList(){
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head = null;
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}
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public void insertHead(int x){ //Insert an element at the head
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Link newLink = new Link(x); //Create a new link with a value attached to it
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newLink.next = head; //Set the new link to point to the current head
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head = newLink; //Now set the new link to be the head
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}
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public Link deleteHead(){ //Delete the element at the head
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Link temp = head;
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head = head.next; //Make the second element in the list the new head, the Java garbage collector will later remove the old head
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return temp;
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}
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public boolean isEmpty(){ //Returns true if list is empty
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return(head == null);
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}
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public void display(){ //Prints contents of the list
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Link current = head;
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while(current!=null){
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current.displayLink();
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current = current.next;
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}
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System.out.println();
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}
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}
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class Link{
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public int value;
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public Link next; //This is what the link will point to
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public Link(int valuein){
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value = valuein;
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}
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public void displayLink(){
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System.out.print(value+" ");
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}
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}
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//Example
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public class SinglyLinkedList{
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public static void main(String args[]){
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LinkedList myList = new LinkedList();
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System.out.println(myList.isEmpty()); //Will print true
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myList.insertHead(5);
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myList.insertHead(7);
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myList.insertHead(10);
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myList.display(); // 10(head) --> 7 --> 5
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myList.deleteHead();
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myList.display(); // 7(head) --> 5
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}
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} |