Java/DataStructures/Lists/SinglyLinkedList.java at master · stonehe/Java · GitHub

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/**

* This class implements a SinglyLinked List. This is done

* using SinglyLinkedList class and a LinkForLinkedList Class.

* A linked list is similar to an array, it hold values.

* However, links in a linked list do not have indexes. With

* a linked list you do not need to predetermine it's size as

* it grows and shrinks as it is edited. This is an example of

* a singly linked list. Elements can only be added/removed

* at the head/front of the list.

* @author Unknown

class SinglyLinkedList{

/**Head refered to the front of the list */

private Node head;

/**

* Constructor of SinglyLinkedList

public SinglyLinkedList(){

head = null;

}

/**

* This method inserts an element at the head

* @param x Element to be added

public void insertHead(int x){

Node newNode = new Node(x); //Create a new link with a value attached to it

newNode.next = head; //Set the new link to point to the current head

head = newNode; //Now set the new link to be the head

}

/**

* Inserts a new node at a specified position

* @param head head node of the linked list

* @param data data to be stored in a new node

* @param position position at which a new node is to be inserted

* @return reference of the head of the linked list

Node InsertNth(Node head, int data, int position) {

Node newNode = new Node();

newNode.data = data;

if (position == 0) {

newNode.next = head;

return newNode;

}

Node current = head;

while (--position > 0) {

current = current.next;

}

newNode.next = current.next;

current.next = newNode;

return head;

}

/**

* This method deletes an element at the head

* @return The element deleted

public Node deleteHead(){

Node temp = head;

head = head.next; //Make the second element in the list the new head, the Java garbage collector will later remove the old head

return temp;

}

/**

* Checks if the list is empty

* @return true is list is empty

public boolean isEmpty(){

return(head == null);

}

/**

* Prints contents of the list

public void display(){

Node current = head;

while(current!=null){

System.out.print(current.getValue()+" ");

current = current.next;

}

System.out.println();

}

/**

* Main method

* @param args Command line arguments

public static void main(String args[]){

SinglyLinkedList myList = new SinglyLinkedList();

System.out.println(myList.isEmpty()); //Will print true

myList.insertHead(5);

myList.insertHead(7);

myList.insertHead(10);

myList.display(); // 10(head) --> 7 --> 5

myList.deleteHead();

myList.display(); // 7(head) --> 5

}

/**

* This class is the nodes of the SinglyLinked List.

* They consist of a value and a pointer to the node

* after them.

* @author Unknown

class Node{

/** The value of the node */

public int value;

/** Point to the next node */

public Node next; //This is what the link will point to

/**

* Constructor

* @param valuein Value to be put in the node

public Node(int valuein){

value = valuein;

}

/**

* Returns value of the node

public int getValue(){

return value;

}

Java/DataStructures/Lists/SinglyLinkedList.java at master · stonehe/Java · GitHub

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