Choose an exercise to read its requirements and examples. Hosted code runs currently require owner access.
Normalize event keys and find the first key that occurs exactly once.
Read a small expression one character at a time. Extend your parser as each part unlocks.
Implement overwrite, deletion and exact TTL boundaries with explicit logical time.
Maintain recency, update existing entries and evict the least recently used key.
Find the first completing pair with deterministic index selection.
Merge two ordered arrays while preserving every duplicate.
Track a contiguous window with no repeated characters.
Use binary search to find the first occurrence in a sorted array.
Answer repeated range sums with one prefix pass.
Group words by character counts while preserving first-seen order.
Scan a sorted sequence and return each distinct value once.
Use a stack to check matching delimiters and nesting order.
Sort ranges and merge overlapping or touching closed intervals.
Find the longest root-to-leaf path in a binary tree.
Detect cycles across every component of a directed dependency graph.
Reserve FIFO work, retry safely and reject stale acknowledgements without losing capacity.
Keep worker capacity, FIFO admission and cancellation correct as events overlap.
Recover complete binary messages from split reads without losing an incomplete tail.
Build a task registry, then extend it as new requirements unlock.