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Start here

The basics

Everything before roadmap level 1, coded right here in your browser: write Python, press Run tests, take a hint if you're stuck, then compare with the solution in Python, Java and C++. Start from where you are.

  • I've never codedPick a language, then 20 first programs: if/else, loops, digits and lists. Each one teaches the one thing it needs.Start coding basics →See the list
  • I know a language24 warm-ups on arrays and strings: largest element, reverse, rotate, count characters… Then roadmap level 1.Start the warm-ups →See the list
  • I know a bit, check me5 warm-ups, about 25 minutes, no hints. Pass 4 and go straight to level 1; anything you miss goes on your revise list.Take the quick check →

The whole path

  1. Step 1Learn one languageA crash course video
  2. Step 2Coding basics20 first programs
  3. Step 3Warm-ups24 array and string basics
  4. Step 4Roadmap level 1Two Sum and friends

Skip whatever you already know. Not sure? The quick check tells you in about 25 minutes.