528 lines
12 KiB
Java
528 lines
12 KiB
Java
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/*This is a Java Program to implement a Doubly Linked List. A linked list is a data structure consisting of a group of nodes which together represent a sequence. Under the simplest form, each node is composed of a data and a reference (in other words, a link) to the next node in the sequence. This structure allows for efficient insertion or removal of elements from any position in the sequence. In a doubly linked list each node has two links one pointing to the next node in the list and one pointing to the previous node in the list .*/
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/*
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* Java Program to Implement Doubly Linked List
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*/
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import java.util.Scanner;
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/* Class Node */
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class Node
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{
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protected int data;
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protected Node next, prev;
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/* Constructor */
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public Node()
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{
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next = null;
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prev = null;
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data = 0;
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}
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/* Constructor */
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public Node(int d, Node n, Node p)
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{
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data = d;
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next = n;
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prev = p;
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}
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/* Function to set link to next node */
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public void setLinkNext(Node n)
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{
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next = n;
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}
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/* Function to set link to previous node */
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public void setLinkPrev(Node p)
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{
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prev = p;
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}
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/* Funtion to get link to next node */
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public Node getLinkNext()
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{
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return next;
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}
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/* Function to get link to previous node */
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public Node getLinkPrev()
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{
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return prev;
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}
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/* Function to set data to node */
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public void setData(int d)
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{
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data = d;
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}
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/* Function to get data from node */
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public int getData()
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{
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return data;
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}
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}
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/* Class linkedList */
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class linkedList
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{
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protected Node start;
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protected Node end ;
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public int size;
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/* Constructor */
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public linkedList()
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{
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start = null;
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end = null;
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size = 0;
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}
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/* Function to check if list is empty */
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public boolean isEmpty()
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{
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return start == null;
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}
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/* Function to get size of list */
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public int getSize()
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{
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return size;
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}
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/* Function to insert element at begining */
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public void insertAtStart(int val)
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{
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Node nptr = new Node(val, null, null);
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if(start == null)
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{
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start = nptr;
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end = start;
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}
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else
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{
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start.setLinkPrev(nptr);
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nptr.setLinkNext(start);
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start = nptr;
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}
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size++;
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}
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/* Function to insert element at end */
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public void insertAtEnd(int val)
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{
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Node nptr = new Node(val, null, null);
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if(start == null)
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{
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start = nptr;
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end = start;
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}
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else
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{
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nptr.setLinkPrev(end);
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end.setLinkNext(nptr);
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end = nptr;
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}
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size++;
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}
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/* Function to insert element at position */
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public void insertAtPos(int val, int pos)
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{
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Node nptr = new Node(val, null, null);
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if (pos == 1)
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{
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insertAtStart(val);
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return;
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}
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Node ptr = start;
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for (int i = 2; i <= size; i++)
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{
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if (i == pos)
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{
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Node tmp = ptr.getLinkNext();
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ptr.setLinkNext(nptr);
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nptr.setLinkPrev(ptr);
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nptr.setLinkNext(tmp);
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tmp.setLinkPrev(nptr);
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}
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ptr = ptr.getLinkNext();
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}
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size++ ;
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}
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/* Function to delete node at position */
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public void deleteAtPos(int pos)
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{
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if (pos == 1)
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{
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if (size == 1)
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{
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start = null;
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end = null;
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size = 0;
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return;
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}
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start = start.getLinkNext();
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start.setLinkPrev(null);
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size--;
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return ;
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}
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if (pos == size)
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{
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end = end.getLinkPrev();
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end.setLinkNext(null);
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size-- ;
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}
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Node ptr = start.getLinkNext();
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for (int i = 2; i <= size; i++)
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{
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if (i == pos)
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{
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Node p = ptr.getLinkPrev();
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Node n = ptr.getLinkNext();
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p.setLinkNext(n);
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n.setLinkPrev(p);
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size-- ;
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return;
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}
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ptr = ptr.getLinkNext();
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}
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}
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/* Function to display status of list */
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public void display()
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{
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System.out.print("\nDoubly Linked List = ");
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if (size == 0)
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{
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System.out.print("empty\n");
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return;
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}
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if (start.getLinkNext() == null)
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{
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System.out.println(start.getData() );
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return;
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}
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Node ptr = start;
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System.out.print(start.getData()+ " <-> ");
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ptr = start.getLinkNext();
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while (ptr.getLinkNext() != null)
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{
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System.out.print(ptr.getData()+ " <-> ");
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ptr = ptr.getLinkNext();
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}
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System.out.print(ptr.getData()+ "\n");
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}
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}
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/* Class DoublyLinkedList */
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public class DoublyLinkedList
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{
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public static void main(String[] args)
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{
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Scanner scan = new Scanner(System.in);
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/* Creating object of linkedList */
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linkedList list = new linkedList();
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System.out.println("Doubly Linked List Test\n");
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char ch;
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/* Perform list operations */
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do
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{
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System.out.println("\nDoubly Linked List Operations\n");
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System.out.println("1. insert at begining");
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System.out.println("2. insert at end");
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System.out.println("3. insert at position");
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System.out.println("4. delete at position");
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System.out.println("5. check empty");
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System.out.println("6. get size");
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int choice = scan.nextInt();
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switch (choice)
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{
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case 1 :
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System.out.println("Enter integer element to insert");
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list.insertAtStart( scan.nextInt() );
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break;
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case 2 :
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System.out.println("Enter integer element to insert");
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list.insertAtEnd( scan.nextInt() );
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break;
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case 3 :
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System.out.println("Enter integer element to insert");
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int num = scan.nextInt() ;
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System.out.println("Enter position");
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int pos = scan.nextInt() ;
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if (pos < 1 || pos > list.getSize() )
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System.out.println("Invalid position\n");
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else
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list.insertAtPos(num, pos);
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break;
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case 4 :
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System.out.println("Enter position");
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int p = scan.nextInt() ;
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if (p < 1 || p > list.getSize() )
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System.out.println("Invalid position\n");
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else
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list.deleteAtPos(p);
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break;
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case 5 :
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System.out.println("Empty status = "+ list.isEmpty());
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break;
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case 6 :
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System.out.println("Size = "+ list.getSize() +" \n");
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break;
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default :
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System.out.println("Wrong Entry \n ");
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break;
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}
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/* Display List */
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list.display();
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System.out.println("\nDo you want to continue (Type y or n) \n");
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ch = scan.next().charAt(0);
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}
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while (ch == 'Y'|| ch == 'y');
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}
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}
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/*Doubly Linked List Operations
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1. insert at begining
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2. insert at end
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3. insert at position
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4. delete at position
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5. check empty
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6. get size
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1
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Enter integer element to insert
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5
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Doubly Linked List = 5
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Do you want to continue (Type y or n)
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y
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Doubly Linked List Operations
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1. insert at begining
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2. insert at end
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3. insert at position
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4. delete at position
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5. check empty
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6. get size
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1
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Enter integer element to insert
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2
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Doubly Linked List = 2 <-> 5
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Do you want to continue (Type y or n)
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y
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Doubly Linked List Operations
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1. insert at begining
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2. insert at end
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3. insert at position
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4. delete at position
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5. check empty
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6. get size
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2
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Enter integer element to insert
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6
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Doubly Linked List = 2 <-> 5 <-> 6
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Do you want to continue (Type y or n)
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y
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Doubly Linked List Operations
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1. insert at begining
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2. insert at end
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3. insert at position
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4. delete at position
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5. check empty
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6. get size
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1
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Enter integer element to insert
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7
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Doubly Linked List = 7 <-> 2 <-> 5 <-> 6
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Do you want to continue (Type y or n)
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y
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Doubly Linked List Operations
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1. insert at begining
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2. insert at end
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3. insert at position
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4. delete at position
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5. check empty
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6. get size
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3
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Enter integer element to insert
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3
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Enter position
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3
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Doubly Linked List = 7 <-> 2 <-> 3 <-> 5 <-> 6
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Do you want to continue (Type y or n)
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y
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Doubly Linked List Operations
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1. insert at begining
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2. insert at end
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3. insert at position
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4. delete at position
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5. check empty
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6. get size
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4
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Enter position
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2
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Doubly Linked List = 7 <-> 3 <-> 5 <-> 6
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Do you want to continue (Type y or n)
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y
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Doubly Linked List Operations
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1. insert at begining
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2. insert at end
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3. insert at position
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4. delete at position
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5. check empty
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6. get size
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3
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Enter integer element to insert
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4
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Enter position
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4
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Doubly Linked List = 7 <-> 3 <-> 5 <-> 4 <-> 6
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Do you want to continue (Type y or n)
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y
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Doubly Linked List Operations
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1. insert at begining
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2. insert at end
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3. insert at position
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4. delete at position
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5. check empty
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6. get size
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6
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Size = 5
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Doubly Linked List = 7 <-> 3 <-> 5 <-> 4 <-> 6
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Do you want to continue (Type y or n)
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y
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Doubly Linked List Operations
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1. insert at begining
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2. insert at end
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3. insert at position
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4. delete at position
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5. check empty
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6. get size
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4
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Enter position
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1
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Doubly Linked List = 3 <-> 5 <-> 4 <-> 6
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Do you want to continue (Type y or n)
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|
|
y
|
||
|
|
|
||
|
|
Doubly Linked List Operations
|
||
|
|
|
||
|
|
1. insert at begining
|
||
|
|
2. insert at end
|
||
|
|
3. insert at position
|
||
|
|
4. delete at position
|
||
|
|
5. check empty
|
||
|
|
6. get size
|
||
|
|
4
|
||
|
|
Enter position
|
||
|
|
2
|
||
|
|
|
||
|
|
Doubly Linked List = 3 <-> 4 <-> 6
|
||
|
|
|
||
|
|
Do you want to continue (Type y or n)
|
||
|
|
|
||
|
|
y
|
||
|
|
|
||
|
|
Doubly Linked List Operations
|
||
|
|
|
||
|
|
1. insert at begining
|
||
|
|
2. insert at end
|
||
|
|
3. insert at position
|
||
|
|
4. delete at position
|
||
|
|
5. check empty
|
||
|
|
6. get size
|
||
|
|
4
|
||
|
|
Enter position
|
||
|
|
2
|
||
|
|
|
||
|
|
Doubly Linked List = 3 <-> 6
|
||
|
|
|
||
|
|
Do you want to continue (Type y or n)
|
||
|
|
|
||
|
|
y
|
||
|
|
|
||
|
|
Doubly Linked List Operations
|
||
|
|
|
||
|
|
1. insert at begining
|
||
|
|
2. insert at end
|
||
|
|
3. insert at position
|
||
|
|
4. delete at position
|
||
|
|
5. check empty
|
||
|
|
6. get size
|
||
|
|
4
|
||
|
|
Enter position
|
||
|
|
1
|
||
|
|
|
||
|
|
Doubly Linked List = 6
|
||
|
|
|
||
|
|
Do you want to continue (Type y or n)
|
||
|
|
|
||
|
|
y
|
||
|
|
|
||
|
|
Doubly Linked List Operations
|
||
|
|
|
||
|
|
1. insert at begining
|
||
|
|
2. insert at end
|
||
|
|
3. insert at position
|
||
|
|
4. delete at position
|
||
|
|
5. check empty
|
||
|
|
6. get size
|
||
|
|
4
|
||
|
|
Enter position
|
||
|
|
1
|
||
|
|
|
||
|
|
Doubly Linked List = empty
|
||
|
|
|
||
|
|
Do you want to continue (Type y or n)
|
||
|
|
|
||
|
|
y
|
||
|
|
|
||
|
|
Doubly Linked List Operations
|
||
|
|
|
||
|
|
1. insert at begining
|
||
|
|
2. insert at end
|
||
|
|
3. insert at position
|
||
|
|
4. delete at position
|
||
|
|
5. check empty
|
||
|
|
6. get size
|
||
|
|
5
|
||
|
|
Empty status = true
|
||
|
|
|
||
|
|
Doubly Linked List = empty
|
||
|
|
|
||
|
|
Do you want to continue (Type y or n)
|
||
|
|
|
||
|
|
n
|