LEARN BY WATCHING STATE CHANGE
See the algorithm think.
A calm, step-by-step space for turning data structures and algorithms into decisions you can explain.
CURRICULUM · 20 TOPICS
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55 focused lessons build reusable reasoning patterns one state change at a time.
SAVED ON THIS DEVICE
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PATTERNS & PREREQUISITES
Follow the learning path.
Lessons move left to right as earlier ideas unlock new ones. Select any lesson to inspect its path.
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Compare algorithms
Recorded transitions describe each teaching trace; they are not runtime benchmarks or raw operation counts.
THE INPUT
Your data
CHALLENGE MODE
Predict the next state.
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ACTIVE CODE
Keyboard: ← previous · → next · Space play/pause · R reset
ROUND COMPLETE
Run it again, change the input, or carry the idea into the next lesson.