3. Challenge: Fibonacci Sequence
4. Challenge: Linked List K-th From the End
5. Challenge: Linked List Merge
6. Challenge: Queue with Stacks
7. Challenge: FIFO Animal Shelter
8. Challenge: Multi Bracket Validation
9. Challenge: Array Binary Search
10. Challenge: Bread First Traversal
10. Challenge: Find the Maximum Value in a Binary Tree
11. Challenge: Find the Height of a Binary Tree
11. Challenge: Determine if a Binary Tree is Balanced
12. Challenge: Determine if characters in an array are unique