How should I practice LRU Cache Operation Sequence?

Start by reading the full statement, solve the visible examples, then compare the pattern against related CARS24 phone screen problems in FastPrep.

Is LRU Cache Operation Sequence associated with CARS24?

FastPrep tags this as a CARS24 phone screen coding practice problem when the problem catalog has that company and stage context.

LRU Cache Operation Sequence

CARS24● MediumFULLTIMEPHONE SCREEN

Problem statement

Process an ordered sequence of operations on a least recently used cache that starts empty.

[1, key, value] is a put: insert or update the value and make that key most recently used.
[0, key, 0] is a get: return the stored value, or -1 if the key is absent. A successful get makes the key most recently used; a miss does not change recency.

When inserting a new key into a full cache, evict the least recently used key. Updating an existing key does not evict another key. Return only the get results, in operation order. Each operation should take O(1) average time.

Function

lruCache(capacity: int, operations: int[][]) → int[]

Examples

Example 1

capacity = 2operations = [[1,1,1],[1,2,2],[0,1,0],[1,3,3],[0,2,0],[1,4,4],[0,1,0],[0,3,0],[0,4,0]]return = [1,-1,-1,3,4]

Getting key 1 refreshes it, so inserting key 3 evicts key 2. Inserting key 4 later evicts key 1. The get results are [1,-1,-1,3,4].

Example 2

capacity = 1operations = [[1,7,2],[1,7,9],[0,7,0]]return = [9]

The second put replaces key 7 without adding an entry. Its get returns 9.

Constraints

1 <= capacity <= 3000.
0 <= operations.length <= 200000.
Every operation has exactly three integers and starts with 0 or 1.
0 <= key <= 10000.
0 <= value <= 100000.
For a get, the third integer is 0.