How should I practice Segmented Durable Key-Value Store?

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

Is Segmented Durable Key-Value Store associated with OpenAI?

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

Problem · Design

Segmented Durable Key-Value Store

Learn this problem

● Medium

OpenAIFULLTIMEPHONE SCREEN

Problem statement

Simulate a durable string key-value store over an ordered batch of commands. The durable store is an append-only log split greedily across numbered segments, each with capacity 1024 bytes.

Commands

PUT key value: append a record and set key to value using last-write-wins semantics. Return OK. The value is the entire suffix after the second space and may be empty.
GET key: return VALUE:value for a present key, or NOT_FOUND.
RELOAD: discard the in-memory map and reconstruct it by replaying every complete record in segment order. Return OK.
SEGMENTS: return SEGMENTS:s1,s2,..., where each value is the used-byte count of one durable segment in order. With no records, return SEGMENTS:.

Record encoding and segmentation

All keys and values are printable ASCII, so one character occupies one byte. Encode a record as keyLength:keyvalueLength:value, where each length is written in base 10. A record is never split. Before an append that would make the current segment exceed 1024 bytes, start a new segment. Every encoded record is guaranteed to fit in one segment.

Return one result string for every command, in command order.

Function

runSegmentedStore(commands: String[]) → String[]

Examples

Example 1

commands = ["PUT color blue","GET color","PUT color green","RELOAD","GET color","SEGMENTS"]return = ["OK","VALUE:blue","OK","OK","VALUE:green","SEGMENTS:27"]

The two encoded records use 13 and 14 bytes. Reload replays both records, so the later value green wins.

Example 2

commands = ["GET missing","SEGMENTS","PUT a " ,"RELOAD","GET a","SEGMENTS"]return = ["NOT_FOUND","SEGMENTS:","OK","OK","VALUE:","SEGMENTS:4"]

An empty value is durable. Its record is 1:a0:, which uses 4 bytes.

Constraints

1 <= commands.length <= 2000
Commands are well formed and use one of the four documented operation names.
Keys are non-empty printable-ASCII strings of length at most 100 and contain no spaces.
Values contain printable ASCII characters, may contain spaces, and have length at most 900.
The total length of all command strings is at most 2 * 10^5.
Every encoded record uses at most 1024 bytes.