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Quick Summary
Track chat events per user within a fixed trailing time window.
Discard expired timestamps proactively to guarantee constant memory usage.
Support efficient event recording and range-count queries under strict timestamp ordering.
What This Tests
Sliding window management with monotonic input guarantees
Per-entity state isolation using hash maps
Efficient ordered sequence operations and memory pruning
Trade-offs between lazy cleanup and query-time scanning
Common Patterns
Sliding Window
Hashing
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