- First create a link list method for adding data.
- So we create a Node object which contain data and next element reference and two constructor
- Now create add method for custom link list hold the data as link list behavior.
- Now call to toString method for display the list data.
- Now exact call check palindrome
- where inside have first find out middle element of link list data
- and also link list reverse method is there
- after see the exact result for pailindrome method for odd and even list
package com.kartik.linklist;public class Palindrome<T> {public static class Node<T> {// reference to the next node in the chain, or null if there isn't one.Node<T> next;// data carried by this node. could be of any type you need.T data;// Node constructorpublic Node(T dataValue) {next = null;data = dataValue;}// another Node constructor if we want to specify the node to point to.public Node(T dataValue, Node<T> nextValue) {next = nextValue;data = dataValue;}// these methods should be self-explanatorypublic T getData() {return data;}public void setData(T dataValue) {data = dataValue;}public Node<T> getNext() {return next;}public void setNext(Node<T> nextValue) {next = nextValue;}}private Node<T> head;private Node<T> tail;/*** default constructor*/public Palindrome() {}/*** Parameter constructor** @param data*/Palindrome(T data) {Node<T> n1 = new Node<T>(data);this.head = n1;this.tail = n1;}/*** appends the specified element to the end of this list.** @param data*/public void add(T data) {// if we have an empty list, create a new list// and copy its head and tail into current objectif (this.head == null) {Palindrome<T> linkList = (new Palindrome<T>(data));this.head = linkList.head;this.tail = linkList.tail;return;}// we need to add this node 'n' to the end of the listNode<T> n = new Node<T>(data);Node<T> current = this.head, prev = null;while (current != null) {prev = current;current = current.next;}prev.next = n;this.tail = n; // update the tail info as well}public String toString() {String output = "";if (head != null) {Node<T> n = head.getNext();output += "[" + head.getData().toString() + "]-->";while (n != null) {output += "[" + n.getData().toString() + "]-->";n = n.getNext();}}return output;}/*** <ul>* <li>The Tortoise (Slow ptr) and the Hare (fast ptr) start at the* beginning of linked list.</li>* <li>For each iteration, slow ptr moves one step and the fast ptr moves* two steps.</li>* <li>If there is a loop, fast ptr will go around the loop and meet with* slow ptr.</li>* <li>If there is no loop, the fast prt will get to the end of the list* without meeting up with the slow ptr.</li>* </ul>** @purpose This function will find middle element in linkedlist* */public Node<T> findMiddleNode(Node<T> head) {Node<T> slowPointer, fastPointer;slowPointer = fastPointer = head;while (fastPointer != null) {fastPointer = fastPointer.next;if (fastPointer != null && fastPointer.next != null) {slowPointer = slowPointer.next;fastPointer = fastPointer.next;}}return slowPointer;}/*** <ul>* <li>First find out the middle node of link list.</li>* <li>Second from last half to end convert reverse of link list</li>* <li>Compare the first node and reverse of the last node</li>* </ul>** @purpose Function to check if linked list is palindrome or not* @return*/public boolean checkPalindrome() {Node<T> fastPtr = head;// Find middle node using slow and fast pointerNode<T> middleNode = findMiddleNode(fastPtr);// we got head of second partNode<T> secondHead = middleNode.next;// It is end of first part of linked listmiddleNode.next = null;// get reversed linked list for second partNode<T> reverseSecondHead = reverseLinkedList(secondHead);while (fastPtr != null && reverseSecondHead != null) {if (fastPtr.data == reverseSecondHead.data) {fastPtr = fastPtr.next;reverseSecondHead = reverseSecondHead.next;continue;} else {return false;}}return true;}/*** @purpose This is the function of reverse link list* @param currentNode* currentNode* @return previousNode of Node<T> object*/public Node<T> reverseLinkedList(Node<T> currentNode) {// For first node, previousNode will be nullNode<T> previousNode = null;Node<T> nextNode;while (currentNode != null) {nextNode = currentNode.next;// reversing the linkcurrentNode.next = previousNode;// moving currentNode and previousNode by 1 nodepreviousNode = currentNode;currentNode = nextNode;}return previousNode;}public static void main(String[] args) {System.out.println("------------------Integer-------------------");Palindrome<Integer> list = new Palindrome<Integer>();list.add(5);list.add(6);list.add(3);list.add(3);list.add(6);list.add(5);System.out.println(list.toString());System.out.println("Linked list palidrome: "+list.checkPalindrome());System.out.println();System.out.println("------------------String-------------------");Palindrome<String> list2 = new Palindrome<String>();list2.add("Kartik");list2.add("Mandal");list2.add("Saharda");list2.add("kharagpur");list2.add("Westbengal");list2.add("India");list2.add("India");list2.add("Westbengal");list2.add("kharagpur");list2.add("Saharda");list2.add("Mandal");list2.add("Kartik");System.out.println(list2.toString());System.out.println("Linked list palidrome: "+list2.checkPalindrome());}}Out put:------------------Integer-------------------[5]-->[6]-->[3]-->[3]-->[6]-->[5]-->Linked list palidrome: true------------------String-------------------[Kartik]-->[Mandal]-->[Saharda]-->[kharagpur]-->[Westbengal]-->[India]-->[India]-->[Westbengal]-->[kharagpur]-->[Saharda]-->[Mandal]-->[Kartik]-->Linked list palidrome: true
I am Kartik Chandra Mandal from Bangalore, India. Working as software engineer in Java technology. Have good knowledge of OWASP and CSRF in security for applications and it's implementation in Java technology.