LeetLLM
Python 3

Practice

Coding drills for AI systems interviews: state, queues, caches, schedulers, parsers, rate limits, and production invariants.

1
Easy
9
Medium
1
Hard
StatusProblemDifficultyCategoryTestsTime
Stack Trace Reconstructor
Reconstruct exclusive function runtimes from nested start/end profiler events.
stackstate machineprofiling
MediumParsing1 sample / 2 hidden30m
Same-host Crawler
Traverse a web graph in breadth-first order while enforcing same-host and duplicate-visit invariants.
BFSURL parsingvisited set
MediumGraph Traversal1 sample / 1 hidden30m
TTL Key/Value Store
Build a deterministic in-memory store where every read path treats expired keys as missing.
TTLinjected timedictionary
MediumStateful Design1 sample / 1 hidden35m
Dependency Scheduler With Retries
Run a dependency graph deterministically, retry transient failures, and reject invalid graphs.
heapDAGretries
HardScheduling1 sample / 1 hidden45m
Workflow State Machine
Track dependent jobs through legal workflow states with retry and cancellation behavior.
state machinedependenciesretries
MediumScheduling1 sample / 2 hidden40m
Token Bucket Rate Limiter
Model per-key API quotas with deterministic refill math and caller-friendly retry-after decisions.
token bucketretry-aftertime abstraction
MediumRate Limiting1 sample / 1 hidden35m
Idempotent Ledger
Apply account mutations exactly once while preserving retry-safe request semantics.
idempotencyledgerstate machine
MediumStateful Design1 sample / 1 hidden30m
LRU TTL Cache
Combine recency ordering and TTL cleanup without corrupting cache invariants.
OrderedDictLRUTTL
MediumCaching1 sample / 1 hidden35m
Log Error Parser
Summarize top error messages from noisy logs with deterministic tie-breaking.
Countersplitlinessorting
EasyParsing1 sample / 1 hidden20m
In-memory Filesystem
Model directory and file state with predictable path normalization and listing behavior.
triepathsstateful API
MediumStateful Design1 sample / 1 hidden35m
Longest-match Tokenizer
Tokenize text by greedily choosing the longest vocabulary token at each position.
trietokenizerstate machine
MediumParsing1 sample / 2 hidden35m