ByteDance Software Engineer System Design Questions

For efficient performance on ByteDance's content delivery platform, we need a system that caches frequently accessed user data and drops the least recently used data when the capacity is exceeded.
You are to implement an LRU (Least Recently Used) cache.Class Name: LRUCache
- Method Signature: def __init__(self, capacity: int):
- Initializes the LRU cache with positive size capacity.- Method Signature: def get(self, key: int) -> int:
- Returns the value of the key if the key exists, otherwise returns -1.- Method Signature: def put(self, key: int, value: int) -> None:
- Update or insert the value if the key is not already present. When the cache reaches its capacity, it should invalidate the least recently used item before inserting a new item.Example 1:
Input: LRUCache(2);
cache.put(1, 1);
cache.put(2, 2);
cache.get(1);
Output: 1;Example 2:
Input: cache.put(3, 3); // LRU key was 2, evicts key 2
cache.get(2);
Output: -1;Constraints:
- capacity is a positive integer.
- All keys and values are in the range of 1 to 10000.
- The functions get and put are guaranteed to be called on existing keys.

ByteDance aims to provide users with a highly personalized experience based on their preferences. You need to design a class to manage and query user preferences effectively.Class Name: UserPreferences
- Method Signature: def add_preference(self, category: str, preference: str) -> None
- Adds a preference to the user's profile.- Method Signature: def get_preferences(self, category: str) -> List[str]
- Returns a list of preferences for a given category.- Method Signature: def delete_preference(self, category: str, preference: str) -> None
- Deletes a specific preference from a given category.Example 1:
Input: user_prefs = UserPreferences() ;
user_prefs.add_preference('music', 'rock')
user_prefs.get_preferences('music')
Output: ['rock']Example 2:
Input: user_prefs.add_preference('music', 'pop') ;
user_prefs.get_preferences('music')
Output: ['rock', 'pop']Constraints:
- 1 <= len(category) <= 100
- 1 <= len(preference) <= 100
- The same preference may not be added multiple times within the same category.