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.
Write a function to convert from normal numbers to Roman Numerals.
Determine if a triangle is equilateral, isosceles, or scalene.
Given a word, compute the scrabble score for that word.
Determine if a sentence is a pangram.
Manage robot factory settings.
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.
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.
Make sure the brackets and braces all match.
Determine if a word or phrase is an isogram.
Compute the prime factors of a given natural number.
Implement a binary search algorithm.
Implement the classic method for composing secret messages called a square code.
Determine if a number is perfect, abundant, or deficient based on Nicomachus' (60 - 120 CE) classification scheme for natural numbers.
Add the numbers to a minesweeper board
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.
Given a decimal number, convert it to the appropriate sequence of events for a secret handshake.
Implement a program that translates from English to Pig Latin
Run Length Encoding
Implement run-length encoding and decoding.
Write a function to determine if a list is a sublist of another list.
Create a custom set type.
Implement basic list operations
Given a 3 x 4 grid of pipes, underscores, and spaces, determine which number is represented, or whether it is garbled.
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
Given a diagram, determine which plants each child in the kindergarten class is responsible for.
Implement a doubly linked list
Detect palindrome products in a given range.
There exists exactly one Pythagorean triplet for which a + b + c = 1000. Find the product a * b * c.
Detect saddle points in a matrix.
Correctly determine change to be given using the least number of coins
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
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.
Write a function to solve alphametics puzzles.
Compute the result for a game of Hex / Polygon
Simple Linked List
Write a simple linked list implementation that uses Elements and a List
Tally the results of a small football competition.
Take input text and output it transposed.
Output the lyrics to 'The Twelve Days of Christmas'
Calculate the number of steps to reach 1 using the Collatz conjecture
Make a chain of dominoes.
Pick the best hand(s) from a list of poker hands.
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.
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
For want of a horseshoe nail, a kingdom was lost, or so the saying goes. Output the full text of this proverbial rhyme.
Count the rectangles in an ASCII diagram.
Given the size, return a square matrix of numbers in spiral order.
Create a sentence of the form "One for X, one for me."
Create a program to solve a word search puzzle.
Diffie-Hellman key exchange.
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.
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.
Implement complex numbers.
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