LRU Cache

Design and implement a data structure for Least Recently Used (LRU) cache. It should support get and put operations.

get(key): Get the value (which will always be positive) of the key if the key exists in the cache, otherwise return -1.
put(key, value): Set or insert the value if the key is not already present. When the cache reached its capacity, it should invalidate the least recently used item before inserting a new item.

The cache is initialized with a positive capacity.

Can you do both operations in O(1) time complexity?

Input

operations: the operations

Output

the return values of get operations

Examples

Example 1:

Input:

operations = [
  LRUCache 2
  put 1 1
  put 2 2
  get 1
  put 3 3
  get 2
  put 4 4
  get 1
  get 3
  get 4
]

Output: [1, -1, -1, 3, 4]

Explanation:

See input.

Try it yourself

Solution