Build with AI tools and verify normal, boundary, and failure cases. Choose practice or a timed exam.
AI NATIVE
AI Native problem library
Build with AI and verify your work. Practice real-world, algorithm and AI systems problems, then take a timed challenge.
AI Native record
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- Practice
Project search
Search names and tags without changing the input.
Data processingLevel 160 min - Practice
Normalize profile inputs
Clean up strings and report invalid fields.
Data processingLevel 145 min - Practice
Deduplicate events
Keep the latest event per ID in a stable order.
Data processingLevel 145 min - Practice
Paginate search results
Build pagination that handles boundary values.
BackendLevel 130 min - Practice
Sales summary
Group paid orders and rank category totals.
Data processingLevel 260 min - Practice
Merge booking intervals
Merge overlapping or touching booking intervals.
AlgorithmsLevel 260 min - Practice
Rebuild task state
Rebuild the final task list from an action log.
BackendLevel 260 min - Practice
Schedule parallel jobs
Assign jobs to workers and calculate completion times.
ReliabilityLevel 260 min - Practice
Dependency execution order
Produce a valid execution order and detect cycles.
AlgorithmsLevel 390 min - Practice
Lowest-cost routes
Find minimum reachable costs in a directed graph.
AlgorithmsLevel 390 min - Practice
LRU cache simulator
Implement a capacity-limited cache that tracks recency.
BackendLevel 390 min - Practice
Sliding-window rate limiter
Limit requests within each user’s sliding time window.
ReliabilityLevel 390 min - Practice
Repair search filters
Fix whitespace, duplicate tags, defaults, and input mutation in existing code.
Bug repairLevel 145 min - Practice
Repair inventory reservations
Reject insufficient stock and invalid quantities while preserving stock and reservation consistency.
Bug repairLevel 260 min - Practice
Repair an expiring cache
Fix expiration boundaries, updates, and recency in an existing cache.
Bug repairLevel 390 min - Practice
Create shareable slugs
Normalize Unicode labels into stable URL slugs.
Data processingLevel 130 min - Practice
Redact nested secrets
Mask sensitive fields in nested JSON logs.
Security & accessLevel 145 min - Practice
Sort release versions
Compare numeric version segments with stable ties.
AlgorithmsLevel 145 min - Practice
Plan API retries
Apply capped exponential backoff and stop conditions.
ReliabilityLevel 130 min - Practice
Repair cursor pagination
Repair mutation and off-by-one cursor behavior.
Bug repairLevel 145 min - Practice
Parse quoted CSV
Handle embedded commas, newlines and escaped quotes.
Data processingLevel 260 min - Practice
Deduplicate payment webhooks
Apply each event ID once and aggregate account balances.
BackendLevel 260 min - Practice
Evaluate access policies
Evaluate wildcard rules with deny overriding allow.
Security & accessLevel 260 min - Practice
Apply JSON merge patches
Merge nested objects, delete null fields and replace arrays.
BackendLevel 260 min - Practice
Roll up service telemetry
Bucket requests and aggregate errors and durations.
Data processingLevel 260 min - Practice
Optimize AI context budgets
Maximize context priority under a token budget.
AI & RAGLevel 390 min - Practice
Rank vector retrieval results
Rank cosine similarity with zero vectors and stable ties.
AI & RAGLevel 390 min - Practice
Chunk overlapping RAG tokens
Preserve overlap and correctly stop at the final chunk.
AI & RAGLevel 375 min - Practice
Build a circuit breaker
Track consecutive failures and exact cooldown boundaries.
ReliabilityLevel 390 min - Practice
Compute rolling medians
Maintain sliding medians for odd and even windows.
AlgorithmsLevel 390 min
Five challenges for first-time makers
- 0-120–40 min
Build and commit your first page
Replace the starter heading and introduction with your own story, check it locally, and push it to GitHub.
A personal introduction page you can open in a browser
- 0-230–50 min
Make a page react to a button
Connect the button to a counter. You can ask AI for code, but click the button yourself to check the result.
A counter that increases with every click
- 0-340–60 min
Add a task to a tiny to-do list
Move entered text into a list. Reject blank input and let users delete individual tasks.
A page that displays the tasks you enter
- 0-440–60 min
Search a project list
Filter the provided project cards by name. Show all cards when the query is empty.
A project list filtered by the search query
- 0-530–50 min
Fix a broken calculator
Find and fix a bug that joins two numbers as text instead of adding them.
A calculator that adds two numbers correctly