LRU Cache With TTL Eviction

Implement an LRU cache with TTL support. The cache must evict the least recently used item when it reaches capacity, and it must also treat expired items as missing.

You are given a sequence of operations to apply to the cache. Each operation is either put(key, value, ttl, current_time) or get(key, current_time). A put stores key with value and an expiration time of current_time + ttl. A get returns the stored value if the key exists and has not expired at current_time, otherwise it returns -1.

Formal specification

Implement: def lru_cache_ttl(capacity, operations):

• capacity is an integer, the maximum number of unexpired entries the cache can hold.
• operations is a list of operations, where each operation is a list:
  • ['put', key, value, ttl, current_time]
  • ['get', key, current_time]
• Return a list of results for all get operations, in order.

Use current_time as an integer timestamp. An item is expired when current_time >= expire_time.