Exercism is a free online resource for improving programming skills. With a unique blend of learning, practice, and mentorship, Exercism helps users develop fluency in over 67 programming languages. Exercism offers fun coding exercises designed to build your understanding of programming concepts, from "Allergies" to "Zebra Puzzle". You can write code locally using your own space, or use the in-browser editor, which supports all 70 of Exercism's programming languages. Automated analysis provides quick feedback and points for improvement. Exercism users can deepen their knowledge with human mentorship, discovering new and exciting ways to approach an exercise while becoming more familiar with the conventions, idioms, and opinions of a particular programming language. Exercism is a not-for-profit organization registered in the UK and is run by Katrina Owen, Jeremy Walker, and Erik Schierboom. Sign up for free and start exploring languages on Exercism.
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