Add new Racket exercises
One of the easiest ways to add new exercises to the Racket track is to translate them from other language tracks on Exercism. This page lists all of the problem specifications in the common pool of exercises which have not yet been implemented in Racket.
The icon links to the language-independent description of the problem.
The icon links to the canonical test data.
We also link to all the implementations of each exercise in other languages, which you can use for inspiration.
Once you've picked an exercise, follow the instructions in this guide and submit your pull request to the Racket track repository on GitHub.
Create an implementation of the atbash cipher, an ancient encryption system created in the Middle East.
Determine if a triangle is equilateral, isosceles, or scalene.
Determine if a sentence is a pangram.
Produce the lyrics to that beloved classic, that field-trip favorite: 99 Bottles of Beer on the Wall.
Given an age in seconds, calculate how old someone is in terms of a given planet's solar years.
Largest Series Product
Given a string of digits, calculate the largest product for a contiguous substring of digits of length n.
Manage robot factory settings.
Sum Of Multiples
Given a number, find the sum of all the multiples of particular numbers up to but not including that number.
Given students' names along with the grade that they are in, create a roster for the school
Given a number determine whether or not it is valid per the Luhn formula.
Implement a clock that handles times without dates.
Compute Pascal's triangle up to a given number of rows.
Use the Sieve of Eratosthenes to find all the primes from 2 up to a given number.
Given a number n, determine what the nth prime is.
All Your Base
Convert a number, represented as a sequence of digits in one base, to any other base.
Determine if a word or phrase is an isogram.
Calculate the date of meetups.
Make sure the brackets and braces all match.
Compute the prime factors of a given natural number.
Implement the classic method for composing secret messages called a square code.
Given a string of digits, output all the contiguous substrings of length `n` in that string.
Implement a binary search algorithm.
Add the numbers to a minesweeper board
Given a decimal number, convert it to the appropriate sequence of events for a secret handshake.
Parse and evaluate simple math word problems returning the answer as an integer.
Implement a program that translates from English to Pig Latin
Given the position of two queens on a chess board, indicate whether or not they are positioned so that they can attack each other.
Take a nested list and return a single list with all values except nil/null
Run Length Encoding
Implement run-length encoding and decoding.
Write a function to determine if a list is a sublist of another list.
Binary Search Tree
Insert and search for numbers in a binary tree.
Create a custom set type.
Given a 3 x 4 grid of pipes, underscores, and spaces, determine which number is represented, or whether it is garbled.
Detect palindrome products in a given range.
Detect saddle points in a matrix.
Implement the `keep` and `discard` operation on collections. Given a collection and a predicate on the collection's elements, `keep` returns a new collection containing those elements where the predicate is true, while `discard` returns a new collection containing those elements where the predicate is false.
Correctly determine change to be given using the least number of coins
Given a diagram, determine which plants each child in the kindergarten class is responsible for.
Implement a doubly linked list
There exists exactly one Pythagorean triplet for which a + b + c = 1000. Find the product a * b * c.
A data structure that uses a single, fixed-size buffer as if it were connected end-to-end.
Calculate the number of steps to reach 1 using the Collatz conjecture
Generate the lyrics of the song 'I Know an Old Lady Who Swallowed a Fly'
Given a string representing a matrix of numbers, return the rows and columns of that matrix.
Implement a simple shift cipher like Caesar and a more secure substitution cipher
Simulate a bank account supporting opening/closing, withdraws, and deposits of money. Watch out for concurrent transactions!
Given a letter, print a diamond starting with 'A' with the supplied letter at the widest point.
Create an implementation of the rotational cipher, also sometimes called the Caesar cipher.
Implement an evaluator for a very simple subset of Forth
Output the nursery rhyme 'This is the House that Jack Built'.
Implement a basic reactive system.
Simple Linked List
Write a simple linked list implementation that uses Elements and a List
Write a function to solve alphametics puzzles.
Compute the result for a game of Hex / Polygon
Pick the best hand(s) from a list of poker hands.
Tally the results of a small football competition.
Take input text and output it transposed.
Output the lyrics to 'The Twelve Days of Christmas'
Create a sentence of the form "One for X, one for me."
Make a chain of dominoes.
Parallel Letter Frequency
Count the frequency of letters in texts using parallel computation.
Translate RNA sequences into proteins.
Variable Length Quantity
Implement variable length quantity encoding and decoding.
To try and encourage more sales of different books from a popular 5 book series, a bookshop has decided to offer discounts of multiple-book purchases.
For want of a horseshoe nail, a kingdom was lost, or so the saying goes. Output the full text of this proverbial rhyme.
Rail Fence Cipher
Implement encoding and decoding for the rail fence cipher.
Creating a zipper for a binary tree.
Reparent a graph on a selected node
Count the rectangles in an ASCII diagram.
Given the size, return a square matrix of numbers in spiral order.
Create a program to solve a word search puzzle.
Implement complex numbers.
Diffie-Hellman key exchange.
Generate musical scales, given a starting note and a set of intervals.
Given two buckets of different size, demonstrate how to measure an exact number of liters.
Implement various kinds of error handling and resource management
Refactor a Markdown parser
Parsing a Smart Game Format string.
Write a Domain Specific Language similar to the Graphviz dot language
Count the scored points on a Go board.
Implement the logic of the hangman game using functional reactive programming.
Refactor a ledger printer.
Use lenses to update nested records (specific to languages with immutable data).
Refactor a tree building algorithm.
Report network IO statistics