private LinkedList_Node <int> MergeAlternateNodes(LinkedList_Node <int> list1, LinkedList_Node <int> list2)
{
if (list1 == null)
{
return(list2);
}
if (list2 == null)
{
return(list1);
}
var list1_temp = list1;
var list2_temp = list2;
var retNode = list1_temp;
while (list1 != null && list2 != null)
{
list1_temp = list1.next;
list2_temp = list2.next;
list1.next = list2;
list1.next.next = list1_temp;
list1 = list1.next.next;
list2 = list2_temp;
}
return(retNode);
}
private LinkedList_Node <int> DivideList(LinkedList_Node <int> node)
{
LinkedList_Node <int> oldHead = node;
int mid = GetLength(node) / 2;
if (node.next == null)
{
return(node);
}
while (mid - 1 > 0)
{
oldHead = oldHead.next;
mid--;
}
LinkedList_Node <int> newHead = oldHead.next;
oldHead.next = null;
oldHead = node; // make one pointer points at the beginning of the first half of the list
LinkedList_Node <int> t1 = DivideList(oldHead);
LinkedList_Node <int> t2 = DivideList(newHead);
return(MergeList(t1, t2));
}
private LinkedList_Node <int> MergeList(LinkedList_Node <int> t1, LinkedList_Node <int> t2)
{
if (t1 == null)
{
return(t2);
}
if (t2 == null)
{
return(t1);
}
LinkedList_Node <int> t = null;
if (t1.data < t2.data)
{
t = t1;
t.next = MergeList(t1.next, t2);
}
else
{
t = t2;
t.next = MergeList(t1, t2.next);
}
return(t);
}
private LinkedList_Node <int> MoveEvenNodesToEndOfList(LinkedList_Node <int> node)
{
LinkedList_Node <int> oddNode = node;
LinkedList_Node <int> evenNode = null, prev = null;
while (oddNode != null && oddNode.next != null)
{
if (oddNode.next != null)
{
var newNode = oddNode.next;
oddNode.next = oddNode.next.next;
newNode.next = evenNode;
evenNode = newNode;
}
prev = oddNode;
oddNode = oddNode.next;
}
if (oddNode != null)
{
oddNode.next = evenNode;
}
else
{
prev.next = evenNode;
}
return(node);
}
private LinkedList_Node <int> InsertAtCorrectPosition(LinkedList_Node <int> head, int val)
{
if (head == null)
{
return(new LinkedList_Node <int>(val));
}
// Inserting node at header
if (head.data >= val)
{
var temp = new LinkedList_Node <int>(val);
temp.next = head;
return(temp);
}
// Inserting at Middle or Last
var retNode = head;
while (head != null && head.next != null && head.next.data < val)
{
head = head.next;
}
var next = head.next;
var newNode = new LinkedList_Node <int>(val);
head.next = newNode;
newNode.next = next;
return(retNode);
}
private void PrintNode(LinkedList_Node <int> node)
{
while (node != null)
{
Console.WriteLine(node.data);
node = node.next;
}
}
private LinkedList_Node <int> MergeTwoSortedLists(LinkedList_Node <int> list1, LinkedList_Node <int> list2)
{
if (list1 == null)
{
return(list2);
}
if (list2 == null)
{
return(list1);
}
LinkedList_Node <int> retNode = null;
if (list1.data < list2.data)
{
retNode = list1;
list1 = list1.next;
}
else
{
retNode = list2;
list2 = list2.next;
}
var result = retNode;
while (list1 != null && list2 != null)
{
if (list1.data < list2.data)
{
retNode.next = list1;
list1 = list1.next;
retNode = retNode.next;
}
else
{
retNode.next = list2;
list2 = list2.next;
retNode = retNode.next;
}
}
if (list1 != null)
{
retNode.next = list1;
}
if (list2 != null)
{
retNode.next = list2;
}
return(result);
}
private LinkedList_Node <int> AddNodeAtFront(LinkedList_Node <int> node, int[] arr)
{
for (int i = 0; i < arr.Length; i++)
{
var temp = new LinkedList_Node <int>(arr[i]);
temp.next = node;
node = temp;
}
return(node);
}
private int GetLength(LinkedList_Node <int> node)
{
int count = 0;
LinkedList_Node <int> temp = node;
while (temp != null)
{
temp = temp.next;
count++;
}
return(count);
}
public void Push(int value)
{
if (list == null)
{
list = new LinkedList_Node <int>(value);
}
else
{
var temp = new LinkedList_Node <int>(value);
temp.next = list;
list = temp;
}
}
private LinkedList_Node <int> ReverseLinkedList_Recursive(LinkedList_Node <int> curr, LinkedList_Node <int> prev, LinkedList_Node <int> head)
{
if (curr == null)
{
head = prev;
return(head);
}
head = ReverseLinkedList_Recursive(curr.next, curr, head);
curr.next = prev;
return(head);
}
public LinkedList_Node <int> Pop()
{
var curr = list;
if (curr == null)
{
return(null);
}
else
{
var next = curr.next;
list = next;
}
return(curr);
}
public void Enqueue(int value)
{
LinkedList_Node <int> node = new LinkedList_Node <int>(value);
if (front == null)
{
front = node;
rear = node;
}
else
{
rear.next = node;
rear = node;
}
}
public LinkedList_Node <int> Dequeue()
{
if (front == null)
{
return(null);
}
LinkedList_Node <int> temp = front;
front = front.next;
if (front == null)
{
rear = null;
}
return(temp);
}
private LinkedList_Node <int> ReverseLinkedList_Iterative(LinkedList_Node <int> head)
{
if (head == null || head.next == null)
{
return(head);
}
LinkedList_Node <int> prev = null;
LinkedList_Node <int> current = head;
while (current != null)
{
LinkedList_Node <int> next = current.next;
current.next = prev;
prev = current;
current = next;
}
return(prev);
}
private LinkedList_Node <int> IntersectionOfTwoSortedLists(LinkedList_Node <int> list1, LinkedList_Node <int> list2)
{
if (list1 == null || list2 == null)
{
return(null);
}
LinkedList_Node <int> head = null, tail = null;
while (list1 != null && list2 != null)
{
if (list1.data == list2.data)
{
if (head == null)
{
tail = head = new LinkedList_Node <int>(list1.data);
}
else
{
tail = tail.next = new LinkedList_Node <int>(list1.data);
}
list1 = list1.next;
list2 = list2.next;
}
else if (list1.data < list2.data)
{
list1 = list1.next;
}
else
{
list2 = list2.next;
}
}
return(head);
}
private LinkedList_Node <int> AddNodeAtLast(LinkedList_Node <int> node, int[] arr)
{
if (node == null)
{
node = new LinkedList_Node <int>();
}
LinkedList_Node <int> retNode = node;
for (int i = 0; i < arr.Length; i++)
{
node.data = arr[i];
if (i != arr.Length - 1)
{
node.next = new LinkedList_Node <int>();
}
else
{
node.next = null;
}
node = node.next;
}
return(retNode);
}
private LinkedList_Node <int> RemoveDuplicatesOnSortedNodes(LinkedList_Node <int> node)
{
LinkedList_Node <int> retNode = node;
if (node == null || node.next == null)
{
return(node);
}
while (node != null && node.next != null)
{
if (node.data == node.next.data)
{
var nextNext = node.next.next;
node.next = nextNext;
}
else
{
node = node.next;
}
}
return(retNode);
}
private void MoveFrontNodeOfListToAnotherList(LinkedList_Node <int> list1, LinkedList_Node <int> list2)
{
if (list1 == null || list2 == null)
{
Console.WriteLine("Invalid Input");
}
Console.WriteLine("Before ListNode1 - ");
PrintNode(list1);
Console.WriteLine("Before ListNode2 - ");
PrintNode(list2);
LinkedList_Node <int> retSecondNode = list2.next;
list2.next = null;
list2.next = list1;
list1 = list2;
list2 = retSecondNode;
Console.WriteLine("After ListNode1 - ");
PrintNode(list1);
Console.WriteLine("After ListNode2 - ");
PrintNode(list2);
}
