Problems from LeetCode and GeeksForGeeks.

1. Linked Lists -

   1. Add Two Numbers
   2. Basic Operations (insert all 3, delete, reverse, Length, Swap Nodes, Swap Nodes in Pairs, etc)
   3. Convert Binary Number To A Linked List.
   4. Convert Sorted List To A Binary Search Tree.
   5. Flatten MultiLevel Doubly Linked List.
   6. Get Middle Element.
   7. Intersection Node.
   8. Linked List Cycle Detection.
   9. Merge K Sorted Lists.
   10. Merge Sort.
   11. Merge Two Sorted Lists.
   12. Odd Even Linked List.
   13. Palindrome Linked List.
   14. Partition List.
   15. Remove Duplicates From Sorted List.
   16. Remove Duplicates From Sorted List II.
   17. Reverse Doubly Linked List.
   18. Reverse List II.
   19. Reverse List In K Groups.
   20. Rotate List.
   21. Rotate List By Right.

2. Stack -

   1. Binary Tree Inorder Traversal(Iterative).
   2. Binary Tree Postorder Traversal(Iterative).
   3. Binary Tree Preorder Traversal(Iterative).
   4. Implement Queue using Stacks.
   5. Implement Stack Using Queue.
   6. Mininmum Stack.
   7. Next Greater Element I.
   8. Next Greater Element II.
   9. Next Greater Element III.
   10. Remove K Digits.
   11. Reverse String Using Stack.
   12. Stack Implementation(Array).
   13. Stack Implementation(LL).
   14. Valid Parentheses.

3. Queue -

   1. BFS Graph.
   2. Queue LinkedList Implementation.
   3. Reverse A Queue.

4. Trees -

   1. Applications Of Binary Tree.
   2. Balanced Binary Tree.
   3. Binary Level Order Traversal.
   4. Binary Tree Zig Zag Order Traversal.
   5. Binary Tree Right Side View.
   6. Convert Binary Tree From Inorder And Postorder.
   7. Convert Binary Tree From Inorder And Preorder.
   8. Convert Sorted Array To Binary Search Tree.
   9. Deletion.
   10. Diameter Of Given Binary Tree.
   11. Flatten Binary Tree To Linked Lists.
   12. Insertion.
   13. Invert Binary Tree.
   14. Kth Samllest Element in Binary Search Tree.
   15. Lowest Commmon Ancestor Of BST.
   16. Lowest Common Ancestor Of Binary Tree.
   17. Merge Two Binary Tree.
   18. Minimum Depth Of Binary Tree.
   19. Path Sum.
   20. Path Sum II.
   21. Recover BST.
   22. Same Tree.
   23. Sum Root To Leaf Number.
   24. Unique BST.
   25. Unique BST II.
   26. Validate BST.