LRU Cache

medium

data-structureTime: O(1)Space: O(n)Frequency: 5

Design a Least Recently Used cache supporting get and put operations in O(1) time.

Example 1:

Input: ["LRUCache", "put", "put", "get", "put", "get", "put", "get", "get", "get"]
       [[2], [1,1], [2,2], [1], [3,3], [2], [4,4], [1], [3], [4]]
Output: [null, null, null, 1, null, -1, null, -1, 3, 4]
Explanation: Cache capacity=2. When put(3,3) is called, key 2 is evicted (least recently used).
             When put(4,4) is called, key 1 is evicted.

hash-maplinked-list

Shortcuts

SubmitCtrl↵
Toggle commentCtrl/
Find in codeCtrlF
UndoCtrlZ
Exit fullscreenEsc

Interview tips

→Aim for O(1) time and O(n) space.
→Walk through your approach with a small example first.
→Handle edge cases: empty input, single element, overflow.
→Code is auto-saved as you type — refresh-safe.

data-structureTime: O(1)Space: O(n)Frequency: 5

Design a Least Recently Used cache supporting get and put operations in O(1) time.

Example 1:

Input: ["LRUCache", "put", "put", "get", "put", "get", "put", "get", "get", "get"]
       [[2], [1,1], [2,2], [1], [3,3], [2], [4,4], [1], [3], [4]]
Output: [null, null, null, 1, null, -1, null, -1, 3, 4]
Explanation: Cache capacity=2. When put(3,3) is called, key 2 is evicted (least recently used).
             When put(4,4) is called, key 1 is evicted.

hash-maplinked-list