Rotate linked list clockwise by k nodes in swift

Swift program for Rotate linked list clockwise by k nodes. Here mentioned other language solution.

import Foundation
/*
  Swift 4 program for 
  Rotate a list by moving each element 
  k times to the right.
  Or clockwise rotation of linked list 
*/
// Linked list node
class LinkNode
{
	var data: Int;
	var next: LinkNode? ;
	init(_ data: Int)
	{
		self.data = data;
		self.next = nil;
	}
}
class SingleLL
{
	var head: LinkNode? ;
	var tail: LinkNode? ;
	init()
	{
		self.head = nil;
		self.tail = nil;
	}
	// Add new Node at end of linked list 
	func addNode(_ data: Int)
	{
		let node: LinkNode? = LinkNode(data);
		if (self.head == nil)
		{
			self.head = node;
		}
		else
		{
			// Append the node at last position
			self.tail!.next = node;
		}
		self.tail = node;
	}
	// Display linked list element
	func display()
	{
		if (self.head == nil)
		{
			print("\n Empty linked list");
			return;
		}
		var temp: LinkNode? = self.head;
		// iterating linked list elements
		while (temp  != nil)
		{
			print("",temp!.data, terminator: " →");
			// Visit to next node
			temp = temp!.next;
		}
		print(" NULL");
	}
	// This are perform the linked list rotation
	func rotation(_ k: Int)
	{
		// Define some auxiliary variable
		var auxiliary: LinkNode? = self.head;
		var count: Int = 0;
		// Count number of node in linked list
		while (auxiliary  != nil)
		{
			// visit to next node
			auxiliary = auxiliary!.next;
			count += 1;
		}
		if (count <= 1)
		{
			// When have less than 2 nodes in linked list
			return;
		}
		// Get actual rotation
		count = k % count;
		if (count == 0)
		{
			// When actual linked list are not affected
			return;
		}
		auxiliary = self.head;
		// Find the rotational node
		while (count > 1)
		{
			// Visit to next node
			auxiliary = auxiliary!.next;
			count -= 1;
		}
		// Connecting the last node to first node of linked list
		self.tail!.next = self.head;
		// Set new last node
		self.tail = auxiliary;
		// Set new head
		self.head = auxiliary!.next;
		// Set that there is no node after of tail
		self.tail!.next = nil;
	}
	// Handles the request to perform rotation
	// k is indicate node rotation
	func clockwiseRotation(_ k: Int)
	{
		if (k <= 0)
		{
			// When invalid given k
			return;
		}
		if (self.head == nil)
		{
			print("\n Empty Linked List");
			return;
		}
		// Display given linked list
		print(" Before rotate ");
		print(" Linked List : ");
		self.display();
		print(" Given k :",k);
		// Perform rotation
		self.rotation(k);
		// Display resultant linked list
		print(" After rotate ");
		print(" Linked List : ");
		self.display();
		print("\n");
	}
	static func main()
	{
		let sll1: SingleLL = SingleLL();
		let sll2: SingleLL = SingleLL();
		// First linked list
		// 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → NULL
		sll1.addNode(1);
		sll1.addNode(2);
		sll1.addNode(3);
		sll1.addNode(4);
		sll1.addNode(5);
		sll1.addNode(6);
		sll1.addNode(7);
		sll1.addNode(8);
		// Second linked list
		// 4 → 9 → 7 → 3 → 8 → 6 → -2 → NULL
		sll2.addNode(4);
		sll2.addNode(9);
		sll2.addNode(7);
		sll2.addNode(3);
		sll2.addNode(8);
		sll2.addNode(6);
		sll2.addNode(-2);
		// Test case
		sll1.clockwiseRotation(3);
		sll2.clockwiseRotation(18);
	}
}
SingleLL.main();

Output

 Before rotate
 Linked List :
 1 → 2 → 3 → 4 → 5 → 6 → 7 → 8 → NULL
 Given k : 3
 After rotate
 Linked List :
 4 → 5 → 6 → 7 → 8 → 1 → 2 → 3 → NULL


 Before rotate
 Linked List :
 4 → 9 → 7 → 3 → 8 → 6 → -2 → NULL
 Given k : 18
 After rotate
 Linked List :
 8 → 6 → -2 → 4 → 9 → 7 → 3 → NULL