# Elm

When you're logged in, you can say `exercism fetch elm` to get the next available exercise on the track.

Every time you submit a solution to an exercise, you will get the next in line the next time you fetch.

If you want to try a specific exercise, you can always fetch it directly (commands are listed below).

The exercises are ordered roughly in order of difficulty.

### Available Exercises

• Hello World The classical introductory exercise. Just say "Hello, World!"
• Bob Bob is a lackadaisical teenager. In conversation, his responses are very limited.
• Twelve Days Output the lyrics to 'The Twelve Days of Christmas'
• Leap Given a year, report if it is a leap year.
• Raindrops Convert a number to a string, the contents of which depend on the number's factors.
• Pangram Determine if a sentence is a pangram.
• Accumulate Implement the `accumulate` operation, which, given a collection and an operation to perform on each element of the collection, returns a new collection containing the result of applying that operation to each element of the input collection.
• Triangle Determine if a triangle is equilateral, isosceles, or scalene.
• Scrabble Score Given a word, compute the scrabble score for that word.
• Anagram Given a word and a list of possible anagrams, select the correct sublist.
• Space Age Given an age in seconds, calculate how old someone is in terms of a given planet's solar years.
• Strain 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.
• Difference Of Squares Find the difference between the square of the sum and the sum of the squares of the first N natural numbers.
• Word Count Given a phrase, count the occurrences of each word in that phrase.
• Sum Of Multiples Given a number, find the sum of all the multiples of particular numbers up to but not including that number.
• Hamming Calculate the Hamming difference between two DNA strands.
• Rna Transcription Given a DNA strand, return its RNA Complement Transcription.
• Run Length Encoding Implement run-length encoding and decoding.
• Sublist Write a function to determine if a list is a sublist of another list.
• Nucleotide Count Given a DNA string, compute how many times each nucleotide occurs in the string.
• Series Given a string of digits, output all the contiguous substrings of length `n` in that string.
• Phone Number Clean up user-entered phone numbers so that they can be sent SMS messages.
• Grade School Given students' names along with the grade that they are in, create a roster for the school
• Allergies Given a person's allergy score, determine whether or not they're allergic to a given item, and their full list of allergies.
• Robot Simulator Write a robot simulator.
• List Ops Implement basic list operations
• Atbash Cipher Create an implementation of the atbash cipher, an ancient encryption system created in the Middle East.
• Say Given a number from 0 to 999,999,999,999, spell out that number in English.
• Largest Series Product Given a string of digits, calculate the largest product for a contiguous substring of digits of length n.
• Roman Numerals Write a function to convert from normal numbers to Roman Numerals.
• Gigasecond Calculate the moment when someone has lived for 10^9 seconds.
• Grains Calculate the number of grains of wheat on a chessboard given that the number on each square doubles.
• Etl We are going to do the `Transform` step of an Extract-Transform-Load.
• Collatz Conjecture Calculate the number of steps to reach 1 using the Collatz conjecture
• Acronym 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.
• Pascals Triangle Compute Pascal's triangle up to a given number of rows.
• Isogram Determine if a word or phrase is an isogram.
• Luhn Given a number determine whether or not it is valid per the Luhn formula.
• Transpose Take input text and output it transposed.
• Binary Search Implement a binary search algorithm.