1. Design In-Memory File System: Implement a class to design an in-memory file system with operations like ls, mkdir, addContentToFile, and readContentFromFile using a hash table.

2. LFU Cache: Write a class to design a Least Frequently Used (LFU) cache using a hash table and a doubly linked list.

3. Word Pattern II: Implement a function to determine if a pattern matches a string with unique substrings using a hash table.

4. All Possible Full Binary Trees: Write a function to generate all possible full binary trees with n nodes using a hash table.

5. Design Search Autocomplete System: Implement a class to design a search autocomplete system with operations like input and search using a hash table.

6. Design Browser History: Write a class to design a browser history system with operations like visit, back, and forward using a hash table.

7. Evaluate Division (Optimized): Implement a function to evaluate division equations using an optimized hash table approach.

8. Count Different Palindromic Subsequences: Write a function to count the different palindromic subsequences in a string using a hash table.

9. Analyze User Website Visit Pattern: Implement a function to analyze the user website visit pattern and find the most visited pattern using a hash table.

10. Design File System (Complex): Write a class to design a complex file system with advanced operations using a hash table.

11. Number of Atoms: Implement a function to count the number of atoms in a chemical formula using a hash table.

12. Shortest Distance from All Buildings: Write a function to find the shortest distance from all buildings in a grid using a hash table.

13. Maximum XOR of Two Numbers in an Array: Implement a function to find the maximum XOR of two numbers in an array using a hash table.

14. Minimum Number of Refueling Stops: Write a function to calculate the minimum number of refueling stops to reach a target distance using a hash table.

15. Design Hit Counter: Implement a class to design a hit counter that counts the number of hits in the past 5 minutes using a hash table.

16. Word Abbreviation: Write a function to generate unique abbreviations for words in a list using a hash table.

17. Find Duplicate File in System: Implement a function to find all duplicate files in a system using a hash table.

18. Smallest Range Covering Elements from K Lists: Write a function to find the smallest range that includes at least one element from each of k lists using a hash table.

19. Find And Replace Pattern: Implement a function to find and replace a pattern in a list of words using a hash table.

20. Split Array into Consecutive Subsequences: Write a function to split an array into consecutive subsequences using a hash table.

21. Minimum Window Subsequence: Implement a function to find the minimum window subsequence in a string using a hash table.

22. Binary Tree Maximum Path Sum: Write a function to find the maximum path sum in a binary tree using a hash table.

23. Design a Leaderboard: Implement a class to design a leaderboard with operations like addScore, top, and reset using a hash table.

24. Design Excel Sum Formula: Write a class to design an Excel-like sum formula with operations like set, get, and sum using a hash table.

25. Word Squares: Implement a function to find all possible word squares using a hash table.

26. Find Minimum Time to Finish All Jobs: Write a function to find the minimum time to finish all jobs using a hash table.

27. Design Snake Game: Implement a class to design a snake game with operations like move and getScore using a hash table.

28. Palindrome Pairs: Write a function to find all pairs of indices that form palindrome pairs using a hash table.

29. Longest Substring with At Most K Distinct Characters: Implement a function to find the longest substring with at most k distinct characters using a hash table.

30. Design Add and Search Words Data Structure: Write a class to design a data structure that supports adding and searching words with wildcard support using a hash table.