Learn
Discover
Contribute
More

Sign up Log in

Tracks

/

Common Lisp

/

Exercises

/

Flatten Array

Medium

Overview

Community Solutions

Code practice and mentorship for everyone

Develop fluency in 70 programming languages with our unique blend of learning, practice and mentoring. Exercism is fun, effective and 100% free, forever.

Sign up for free Explore languages

Editions

Exercism
Exercism for Teams
Exercism Research

About

About Exercism
Our team
Contributors
Partners
Individual supporters

Get involved

Exercism Insiders
Contribute
Mentor
Donate

Legal & policies

Terms of usage
Privacy policy
Cookie policy
Code of conduct
Accessibility statement

Keep in touch

Exercism's blog
Discuss on GitHub
Contact us
Report abuse

Get help

Exercism's Docs
Getting started
FAQs
Installing the CLI
Interactive CLI Walkthrough

Our programming language tracks

8th
ABAP
AWK
Ballerina
Bash
C
C#
C++
CFML
Clojure
COBOL
CoffeeScript
Common Lisp
Crystal

D
Dart
Delphi Pascal
Elixir
Elm
Emacs Lisp
Erlang
Euphoria
F#
Fortran
Gleam
Go
Groovy
Haskell

Java
JavaScript
jq
Julia
Kotlin
LFE
Lua
MIPS Assembly
Nim
Objective-C
OCaml
Perl
Pharo
PHP

PL/SQL
PowerShell
Prolog
PureScript
Pyret
Python
R
Racket
Raku
ReasonML
Red
Ruby
Rust
Scala

Scheme
SQLite
Standard ML
Swift
Tcl
TypeScript
Unison
V
Vim script
Visual Basic
WebAssembly
Wren
x86-64 Assembly
Zig

Want to add a language track to Exercism?

Start a new topic in the forum and let's discuss it.

Exercism is a not-for-profit organisation registered in the UK. Its trustees are Katrina Owen, Jeremy Walker and Erik Schierboom.

Language Tracks

#48in24 Challenge

Your Journey

Exercism Perks

Community Videos

Brief Introduction Series

Interviews & Stories

Discord

Forum

Getting started

Mentoring

Docs

Contributors

Donate

About Exercism

Our Impact

Insiders

SWAG