JamesJi9277

//is valid palindrome
//reverse and compare, time complexity O(n), space complexity O(n)
public class Solution1{
	public boolean isValidPalindrome(LinkedListNode head){
		LinkedListNode l1 = head;
		LinkedListNode l2 = head;
		while(l1 != null && l1.next != null)
		{
			LinkedListNode before = new LinkedListNode;
			before.next = l2;

JamesJi9277

//Given a circular linked list, implement an algorithm which returns the node at the begining of the loop
public class Solution{
	public LinkedListNode findBegining(LinkedListNode head){
		LinkedListNode slow = head;
		LinkedListNode fast = head;
		while(fast != null || fast.next != null)
		{
			slow = slow.next;
			fast = fast.next.next;
			if(fast == slow)

JamesJi9277

public class Solution{
	public int kthtoLast(LinkedListNode head, int k){
		if (k < 0|| head == null)
			return -1;
		LinkedListNode p1 = head;
		LinkedListNode p2 = head;
		//moving p2 to reach the position length - k.
		for(int i = 0; i< k - 1; i++)
		{
			p2 = p2.next;

JamesJi9277

public class Solution{
	public int kthtoLast(LinkedListNode head, int k){
		if (k < 0|| head == null)
			return -1;
		LinkedListNode p1 = head;
		LinkedListNode p2 = head;
		//moving p2 to reach the position length - k.
		for(int i = 0; i< k - 1; i++)
		{
			p2 = p2.next;

JamesJi9277

public class Solution{
	public int kthtoLast(LinkedListNode head, int k){
		if (k < 0|| head == null)
			return -1;
		LinkedListNode p1 = head;
		LinkedListNode p2 = head;
		//moving p2 to reach the position length - k.
		for(int i = 0; i< k - 1; i++)
		{
			p2 = p2.next;

JamesJi9277

public class Solution{
	public int kthtoLast(LinkedListNode head, int k){
		if (k < 0|| head == null)
			return -1;
		LinkedListNode p1 = head;
		LinkedListNode p2 = head;
		//moving p2 to reach the position length - k.
		for(int i = 0; i< k - 1; i++)
		{
			p2 = p2.next;

JamesJi9277

public class Solution{
	public int kthtoLast(LinkedListNode head, int k){
		if (k < 0|| head == null)
			return -1;
		LinkedListNode p1 = head;
		LinkedListNode p2 = head;
		//moving p2 to reach the position length - k.
		for(int i = 0; i< k - 1; i++)
		{
			p2 = p2.next;

JamesJi9277

public class Solution{
	public int kthtoLast(LinkedListNode head, int k){
		if (k < 0|| head == null)
			return -1;
		LinkedListNode p1 = head;
		LinkedListNode p2 = head;
		//moving p2 to reach the position length - k.
		for(int i = 0; i< k - 1; i++)
		{
			p2 = p2.next;

JamesJi9277

public class Solution{
	public int kthtoLast(LinkedListNode head, int k){
		if (k < 0|| head == null)
			return -1;
		LinkedListNode p1 = head;
		LinkedListNode p2 = head;
		//moving p2 to reach the position length - k.
		for(int i = 0; i< k - 1; i++)
		{
			p2 = p2.next;

JamesJi9277

public class Solution{
	public int kthtoLast(LinkedListNode head, int k){
		if (k < 0|| head == null)
			return -1;
		LinkedListNode p1 = head;
		LinkedListNode p2 = head;
		//moving p2 to reach the position length - k.
		for(int i = 0; i< k - 1; i++)
		{
			p2 = p2.next;