LinkedIn Mobile Engineer Coding Questions

LinkedIn's mobile platform requires efficient caching to enhance its API responses speed and reduce load on servers. Create an LRU (Least Recently Used) cache that resolves HTTP requests.- Function Signature: def LRUCache(capacity: int) -> None: - Initialize LRU cache system.
- Method 1: def get(key: str) -> Union[int, None]: - Return the value of the key if present, else return None.
- Method 2: def put(key: str, value: int) -> None: - Update or add the value if the key is not already present. If the cache reaches its capacity, it should invalidate the least recently used item.Example 1:
Input: cache = LRUCache(2)
cache.put(1,1)
cache.put(2,2)
cache.get(1)
Output: 1
Explanation: Returns the value for key 1.Example 2:
Input: cache.put(3,3)
cache.get(2)
Output: None
Explanation: Returns None since key 2 was evicted to make space.Constraints:
- 1 <= capacity <= 1000
- 0 <= key <= 10^5
- 0 <= value <= 10^5

LinkedIn users need to manage their messages even in low connectivity scenarios. Your job is to efficiently synchronize a user's messages when the connection is restored.
Given a list of messages, each with an associated timestamp, and a window_size, implement a function to retrieve messages that fall within that time window.- Function Signature: def sync_messages(messages: List[Tuple[str, int]], window_size: int) -> List[str]: - Return a list of messages within the timeframe of window_size.Example 1:
Input: messages = [('msg1', 1), ('msg2', 2), ('msg3', 5)], window_size = 3
Output: ['msg2', 'msg3']
Explanation: msg2 and msg3 are within a 3 second window of the last message.Example 2:
Input: messages = [('msg1', 1), ('msg2', 10), ('msg3', 15)], window_size = 5
Output: []
Explanation: No messages fall within the 5 seconds range.Constraints:
- 1 <= len(messages) <= 10^6
- 0 <= timestamp <= 10^9