Add new Lisp Flavoured Erlang (LFE) exercises
One of the easiest ways to add new exercises to the Lisp Flavoured Erlang (LFE) 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 Lisp Flavoured Erlang (LFE).
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 Lisp Flavoured Erlang (LFE) track repository on GitHub.
The classical introductory exercise. Just say "Hello, World!"
Convert a number to a string, the contents of which depend on the number's factors.
Determine if a triangle is equilateral, isosceles, or scalene.
Write a function to convert from normal numbers to Roman Numerals.
Given a word, compute the scrabble score for that word.
Determine if a sentence is a pangram.
Compute Pascal's triangle up to a given number of rows.
Manage robot factory settings.
Given a number n, determine what the nth prime is.
Use the Sieve of Eratosthenes to find all the primes from 2 up to a given number.
Convert a long phrase to its acronym
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.
Determine if a number is perfect, abundant, or deficient based on Nicomachus' (60 - 120 CE) classification scheme for natural numbers.
Compute the prime factors of a given natural number.
Implement a binary search algorithm.
Make sure the brackets and braces all match.
Calculate the number of steps to reach 1 using the Collatz conjecture
Implement the classic method for composing secret messages called a square code.
Add the numbers to a minesweeper board
Implement a program that translates from English to Pig Latin
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.
Given the position of two queens on a chess board, indicate whether or not they are positioned so that they can attack each other.
Given a number from 0 to 999,999,999,999, spell out that number in English.
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.
Take a nested list and return a single list with all values except nil/null
Implement basic list operations
Run Length Encoding
Implement run-length encoding and decoding.
Create a custom set type.
Implement a doubly linked list
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.
Correctly determine change to be given using the least number of coins
Given a letter, print a diamond starting with 'A' with the supplied letter at the widest point.
Generate the lyrics of the song 'I Know an Old Lady Who Swallowed a Fly'
Given a diagram, determine which plants each child in the kindergarten class is responsible for.
There exists exactly one Pythagorean triplet for which a + b + c = 1000. Find the product a * b * c.
Given a string representing a matrix of numbers, return the rows and columns of that matrix.
Create an implementation of the rotational cipher, also sometimes called the Caesar cipher.
Implement a simple shift cipher like Caesar and a more secure substitution cipher
Take input text and output it transposed.
Create a sentence of the form "One for X, one for me."
Implement an evaluator for a very simple subset of Forth
Implement a basic reactive system.
Output the nursery rhyme 'This is the House that Jack Built'.
Simple Linked List
Write a simple linked list implementation that uses Elements and a List
Tally the results of a small football competition.
Output the lyrics to 'The Twelve Days of Christmas'
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.
Translate RNA sequences into proteins.
Make a chain of dominoes.
Variable Length Quantity
Implement variable length quantity encoding and decoding.
Creating a zipper for a binary tree.
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.
Implement complex numbers.
Diffie-Hellman key exchange.
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.
Given the size, return a square matrix of numbers in spiral order.
Create a program to solve a word search puzzle.
Refactor a Markdown parser
Reparent a graph on a selected node
Count the rectangles in an ASCII diagram.
Given two buckets of different size, demonstrate how to measure an exact number of liters.
Search a file for lines matching a regular expression pattern. Return the line number and contents of each matching line.
Generate musical scales, given a starting note and a set of intervals.
Implement various kinds of error handling and resource management
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
Check if a given string is a valid ISBN-10 number.