Pick a topic and watch it animate — then read the idea in plain English, run the code yourself, and check what stuck. Interview practice is optional.
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The best place to begin — Big-O, time & space. A short, plain-English intro the rest of the course builds on. About 8 minutes.
What each lesson looks like
Learn
the idea in plain English
See it
watch it play out
Warm up
tiny hands-on drills
Practice
run & edit real code
Check
a quick quiz
Every topic follows these five steps — about 4–10 minutes each. No sign-up needed to try your first one.