1. Reverse a linked list recursively.
2. Reverse a doubly linked list recursively.
3. Reverse a circular linked list recursively.
4. Reverse every k nodes of a linked list recursively.
5. Rotate a linked list left by k nodes recursively.
6. Rotate a linked list right by k nodes recursively.
7. Merge two sorted linked lists recursively.
8. Flatten a multilevel linked list.
9. Sort a linked list using merge sort.
10. Sort a linked list using quicksort.
11. Partition a linked list around a given value.
12. Remove every kth node from a linked list.
13. Rearrange a linked list in alternating low-high order.
14. Reverse the alternate nodes of a linked list.
15. Detect a cycle in a linked list using two-pointer technique.
16. Convert a binary search tree to a doubly linked list.
17. Convert a binary tree to a doubly linked list in-place.
18. Convert a binary tree to a circular doubly linked list.
19. Convert a linked list into a binary tree.
20. Find the kth smallest element in a linked list.
21. Find the kth largest element in a linked list.
22. Merge K sorted linked lists.
23. Remove the loop in a linked list.
24. Check if two linked lists intersect.
25. Swap nodes in pairs in a linked list.
26. Clone a linked list with random pointers.
27. Check if a linked list is a palindrome using recursion.
28. Convert a sorted linked list into a balanced binary search tree.
29. Insert a node into a cyclic sorted linked list.
30. Find the length of the longest palindrome in a linked list.
31. Reverse nodes in k-group chunks.
32. Rearrange a linked list in alternating high-low order.
33. Merge two circular linked lists into a single circular list.
34. Delete the middle node of a linked list without knowing the head.
35. Remove nodes with values greater than the following node.
36. Find the nearest smaller node for every node in a linked list.
37. Move the greatest node to the end of the linked list.
38. Detect and remove a cycle in a doubly linked list.
39. Find the starting node of a loop in a circular linked list.
40. Implement a doubly linked list using two singly linked lists.